WO2019098283A1

WO2019098283A1 - Oriented porous film

Info

Publication number: WO2019098283A1
Application number: PCT/JP2018/042311
Authority: WO
Inventors: 隆敏牟田; 祐里桑名
Original assignee: 三菱ケミカル株式会社
Priority date: 2017-11-16
Filing date: 2018-11-15
Publication date: 2019-05-23
Also published as: TW201925294A; TWI795467B

Abstract

This oriented porous film is made from a resin composition (Z) comprising a thermoplastic resin and an inorganic filler (A). The ratio tanδ (=E"/E') of loss modulus (E") to storage modulus (E') calculated from the dynamic viscoelasticity measurement of the resin composition (Z), is at least 0.100 at a temperature of -20°C, and porosity falls within the range of 25% to 80%.

Description

Stretched porous film

The present invention relates to a stretched porous film having excellent feel such as flexibility and texture, suppressing generation of unpleasant sound generated when rubbing the film, and excellent also in air permeability, moisture permeability and strength. More specifically, sanitary products such as disposable diapers and feminine hygiene products; clothing such as work clothes, jumpers, jackets, medical clothes, chemical protective clothing, etc .; other masks, covers, drapes, sheets, wraps, breathable, etc. An excellent stretched porous film having a feeling of use that can be suitably used for applications requiring

Conventionally, by stretching a resin composition containing a thermoplastic resin such as polyolefin resin and an inorganic filler, interfacial peeling is generated between the thermoplastic resin and the inorganic filler, and a large number of voids (microporous) A porous film formed is known. In particular, a stretched porous film made of a resin composition containing a polyolefin resin and an inorganic filler has a fine internal pore forming a communicating hole, so that it can transmit liquid while having high air permeability and moisture permeability. Is used as a moisture-permeable waterproof film that has been controlled, and in particular, sanitary materials such as disposable diapers and feminine hygiene products, work clothes, jumpers, jackets, medical clothes, clothes such as chemical protective clothes, masks, covers, drapes, It is widely used in applications requiring breathability and breathability such as sheets and wraps.

Since the porous film used in these applications is often used directly for touching the human skin, it is desirable that the film has an unpleasant sound or feel such as squeakyness and sizzling when it is worn. It becomes a factor that disturbs the feeling. Therefore, the porous film is required to have a good texture and flexibility and a good touch, and to suppress unpleasant noise.

To these problems, for example, 50 to 300 parts by weight of an inorganic filler is contained with respect to 100 parts by weight of a total amount of ethylene / α-olefin copolymer 65 to 90% by weight and thermoplastic elastomer 35 to 10% by weight. A porous film (Patent Document 1) or a resin comprising 20 to 100 parts by weight of crystalline low density polyethylene containing 12% by weight or more of an α-olefin comonomer having 4 to 8 carbon atoms and 80 to 0 parts by weight of polyethylene A moisture-permeable film (Patent Document 2) is disclosed which contains 50 to 400 parts by weight of an inorganic filler with respect to 100 parts by weight of the component.

In addition, 50 to 300 parts by mass of an inorganic filler and 1 to 30 parts by mass of a plasticizer are included with respect to 100 parts by mass of a total of 30 to 70 parts by mass of a polyethylene resin and 70 to 30 parts by mass of an olefin elastomer. Resin component containing 100 to 40 parts by mass of a hydrophobic film (Patent Document 3), 40 to 90 parts by mass of polyethylene resin, 5 to 30 parts by mass of propylene homopolymer, and 5 to 30 parts by mass of propylene / ethylene copolymer elastomer A moisture-permeable film containing 100 to 200 parts by mass of an inorganic filler and 1 to 20 parts by mass of a plasticizer (Patent Document 4), a moisture-permeable film containing a polyethylene resin composition, an inorganic filler, and a styrene elastomer 5) Further, 30 to 85 parts by mass of linear low density polyethylene, 5 to 20 parts by mass of high pressure polymerization low density polyethylene, metallocene A moisture-permeable film comprising a resin component containing 10 to 50 parts by mass of ethylene / α-olefin copolymer, 100 to 200 parts by mass of an inorganic filler and 1 to 20 parts by mass of a plasticizer based on 100 parts by mass of the resin component (Patent Document 6) are each disclosed.

Furthermore, a resin composition containing a thermoplastic resin, a film containing 80% or less of porosity and containing 1 to 70% by mass of a filler (Patent Document 7), a thermoplastic resin, an organic filler, and an inorganic filler A porous film (Patent Document 8) having a porosity of 10 to 80% is disclosed.

Japanese Patent Application Laid-Open No. 7-228719 JP 2000-1557 A JP, 2017-31292, A JP, 2015-229720, A International Publication 2014/0880665 International Publication 2015/186808 International Publication 2014/156952 JP, 2006-117816, A

However, in Patent Documents 1 and 2, an ethylene / α-olefin copolymer having a melting point of 60 to 100 ° C. and a crystalline low density polyethylene containing 12% by weight or more of an α-olefin comonomer having 4 to 8 carbon atoms are used. Since the film is a main component, it has a high degree of flexibility, but may melt under high temperature conditions generated in the step of bonding other members, etc., resulting in insufficient dimensional stability, heat resistance and the like.

In Patent Documents 3 to 6, in compositions containing a polyethylene resin and an inorganic filler, an olefin elastomer, a propylene / ethylene copolymer elastomer, a styrene elastomer, a metallocene ethylene / α-olefin copolymer, etc. By containing the soft resin of the above, it is possible to obtain a film having flexibility and stretchability, and having an excellent feel and feel.
On the other hand, in applications where these porous films are used, further improvement in the feeling of use is required, so that further improvement in touch feeling such as flexibility and texture, and generation of unpleasant sound generated when rubbing the film Control of the However, Patent Documents 3 to 6 do not refer to technical design guidelines for suppressing unpleasant noise.

Further, in Patent Document 7, a filler is contained in a biodegradable resin typified by a polylactic acid-based resin, and attempts have been made to achieve both water resistance and degradability, and the porosity is 80% or less Although it is described that the water resistance of the film is suppressed by doing so, no mention is made as to suppression of unpleasant noise. Further, Patent Document 8 also describes that lowering the moisture permeability, the film strength, the heat retention effect, and the dustproof effect is suppressed by setting the porosity to 10 to 80%, but similarly, the unpleasant noise There is no mention of the suppression of

The present invention has been made in view of the above problems, and has an excellent tactile sensation such as flexibility and texture, as well as suppressing the generation of unpleasant noise generated when the film is rubbed, and excellent also in air permeability, moisture permeability and strength. It is an object of the present invention to provide a stretched porous film.

As a result of intensive studies, the present inventors succeeded in obtaining a stretched porous film capable of solving the problems of the above-mentioned prior art, and came to complete the present invention. That is, the object of the present invention is achieved by the following stretched porous film (hereinafter, also referred to as "the stretched porous film of the present invention").

That is, an object of the present invention is a stretched porous film comprising a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A), which is calculated from the dynamic viscoelasticity measurement of the resin composition (Z) Ratio of storage elastic modulus (E ′) to loss elastic modulus (E ′ ′), which is equal to or greater than 0.100 at −20 ° C., and a porosity of 25 It is solved by a stretched porous film (the first embodiment of the present invention) which is% -80%.

Another object of the present invention is a stretched porous film comprising a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A), which is calculated from the dynamic viscoelasticity measurement of the resin composition (Z). Ratio of storage elastic modulus (E ′) to loss elastic modulus (E ′ ′), ie, tan δ (= E ′ ′ / E ′) is 0.100 or more at −20 ° C., 140 ° C. to 200 ° C. It is solved by a stretched porous film (second embodiment of the invention) having a crystalline melting peak (Pm1).

According to the present invention, it is possible to obtain a stretched porous film having excellent feel such as softness and texture, suppressing generation of unpleasant sound generated when rubbing the film, and being excellent also in air permeability, moisture permeability and strength. As it can, it can be suitably used for applications requiring breathability and moisture permeability.

Hereinafter, the stretched porous film of the present invention as an example of the embodiment of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below. Here, the stretched porous film is a porous film stretched at least in a uniaxial direction.

In the present specification, "main component" refers to a component that occupies the largest mass ratio in the composition, and is preferably 45 mass% or more, more preferably 50 mass% or more, 55 mass% The above is more preferable. Moreover, when stated as “X to Y” (X and Y are arbitrary numbers), “preferably more than X” and “preferably less than Y” with the meaning of “X or more and Y or less” unless otherwise specified. It includes the meaning of "."

1. Stretched porous film 1-1. Stretched porous film (first embodiment of the present invention)
The stretched porous film of the first embodiment of the present invention is a stretched porous film comprising a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A), and the dynamic of the resin composition (Z) The ratio of the storage elastic modulus (E ′) calculated from the viscoelasticity measurement to the loss elastic modulus (E ′ ′), tan δ (= E ′ ′ / E ′), is 0.100 or more at −20 ° C. It is a stretched porous film having a porosity of 25% to 80%.

The stretched porous film of the first embodiment of the present invention comprises a resin composition (Z) containing 25% by mass to 54% by mass of a thermoplastic resin and 46% by mass to 75% by mass of an inorganic filler (A). Is preferred. Therefore, more preferably, the stretched porous film of the first embodiment of the present invention is a resin composition containing 25% by mass to 54% by mass of a thermoplastic resin and 46% by mass to 75% by mass of an inorganic filler (A). A stretched porous film comprising (Z), which is a ratio of a storage elastic modulus (E ′) to a loss elastic modulus (E ′ ′) calculated from measurement of dynamic viscoelasticity of the resin composition (Z), tan δ It is a stretched porous film having (= E ′ ′ / E ′) of 0.100 or more at −20 ° C. and a porosity of 25% to 80%.

The stretched porous film of the first embodiment of the present invention has a storage elastic modulus (E ′) and a loss elastic modulus (E ′) calculated from dynamic viscoelasticity measurement of a resin composition (Z) constituting the stretched porous film. It is important that tan δ (= E ′ ′ / E ′) which is the ratio of ') is 0.100 or more at -20 ° C., preferably 0.110 or more, and 0.120 or more Is more preferably 0.130 or more. The upper limit of tan δ of the resin composition (Z) constituting the stretched porous film is not particularly limited, but is preferably 1.000 or less at -20 ° C. from the viewpoint of heat resistance and dimensional stability. . The sound absorption coefficient (vibration attenuation factor) for suppressing the unpleasant sound generated when the film is rubbed, as described later, when tan δ (= E ′ ′ / E ′) is 0.100 or more at −20 ° C. The film is excellent in touch such as flexibility and texture.

The tan δ is preferably 0.100 or more at -20 ° C to -10 ° C, more preferably 0.100 or more at -20 ° C to 0 ° C, and 0.100 at -20 ° C to 10 ° C. The above is more preferable, the range of -0.100 or more at -20 ° C to 20 ° C is even more preferable, and the range of 0.100 or more at -30 ° C to 30 ° C is most preferable. As will be described later, the temperature range in which tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention is 0.100 or more is broadened In addition, unpleasant noises of various frequencies can be suppressed.

Furthermore, it is important that the porosity of the stretched porous film of the first embodiment of the present invention is 25% to 80%. The porosity is more preferably 30% to 80%, and still more preferably 35% to 80%.
When the porosity is 25% or more, as described later, the energy loss opportunity of sound propagating in the pores of the stretched porous film increases, and unpleasant noise can be sufficiently suppressed. In addition, when the porosity is 80% or less, it is possible to secure a film strength that can be practically used, and further, the waterproofness is sufficient, and it becomes difficult to cause the leakage of the liquid material in contact.

Sound is an oscillatory wave of air that occurs when an object moves or rubs. When a sound collides with an object as an incident sound, the incident sound is classified into three sounds of a transmitted sound transmitted through the object, a reflected sound reflected the object, and an absorbed sound absorbed by the object from the relation of energy conservation law. It is disassembled. That is, when an incident sound collides with an object, if the ratio of absorbed sound absorbed by the object is large, the object is considered to be an object having a high sound absorption coefficient.
The stretched porous film of the first embodiment of the present invention is a film having a void communicated with the inside of the resin composition (Z). That is, when sound propagates in the stretched porous film of the first embodiment of the present invention, the sound is formed by vibrating the resin composition (Z) forming the solid portion as a film and propagating inside the film It shows two ways of transmission with the sound that propagates through the air gap that has communicated. Therefore, to suppress the sound, it is necessary to consider the suppression of the sound that propagates by vibrating the resin composition (Z), and the suppression of the sound that propagates through the open space.

In the stretched porous film of the first embodiment of the present invention, it is considered that the damping of the sound by the vibration source or medium is effective for the suppression of the sound propagating by vibrating the resin composition (Z). In a viscoelastic body such as a resin, a sound absorbing effect can be obtained by losing the energy of vibration to thermal energy. Therefore, tan δ, which is the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′), is considered to be a necessary element to exhibit this sound absorption effect. Therefore, in the first embodiment of the present invention, it is preferable that the peak value of tan δ of the resin composition (Z) constituting the stretched porous film be larger.
Further, the peak position of tan δ of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention is related to the attenuation at the temperature at which the sound is generated, and from the viewpoint of the temperature-time conversion law. It also relates to the attenuation to the frequency. Therefore, it is preferable that the peak width of tan δ be wider in order to absorb or not generate unpleasant sounds having various frequencies.
Therefore, the storage elastic modulus (E ′) and the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention It is important that tan δ (= E ′ ′ / E ′), which is a ratio of, is not less than 0.100 at −20 ° C. in order to suppress the generation of unpleasant noise generated when the film is rubbed. As described above, it is preferable that the temperature range in which tan δ is 0.100 or more is broadened because unpleasant noises of various frequencies can be suppressed.

Furthermore, in the first embodiment of the present invention, not only the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) tan δ, which is the ratio of the porous film, but also the porosity of the porous film suppresses the propagation of sound. I found that I made a major contribution to The increase in porosity leads to an increase in the number of collisions between the sound propagating in the air and the object, so it is considered that the sound suppression effect transmitted in the air gap formed inside the film is obtained. ing.
Therefore, it is important that the porosity of the stretched porous film is 25% or more in order to increase the chance of energy loss of sound propagating through the pores of the film.

Summarizing the above, the first embodiment of the present invention relates to the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z). A sound absorption coefficient (vibration attenuation factor) for suppressing unpleasant noise generated when the film is rubbed as well as excellent in tactile sensation such as softness and texture by setting the porosity of the film to a certain range. Can be improved).

The stretched porous film of the first embodiment of the present invention preferably has a crystal melting enthalpy (ΔHm) of 10 J / g to 45 J / g. The crystal melting enthalpy (ΔHm) is more preferably 12 J / g to 43 J / g, still more preferably 14 J / g to 41 J / g, and further preferably 16 J / g to 39 J / g. More preferable. When the crystal melting enthalpy (ΔHm) is 10 J / g or more, the heat resistance and the dimensional stability of the stretched porous film can be secured. In addition, when the crystal melting enthalpy (ΔHm) is 45 J / g or less, generation of unpleasant noise described later can be suppressed.

As a method of suppressing the unpleasant sound generated when rubbing the stretched porous film, it is considered effective to suppress the generation of the sound from the sound source as well as suppressing the above-mentioned propagation sound. The generation of sound is the vibration of the elastic body, and no sound is generated unless there is something that causes the vibration (= sound source).
Focusing on the thermoplastic resin contained in the resin composition (Z) constituting the stretched film of the first embodiment of the present invention, the thermoplastic resin is a viscoelastic body having both elastic properties and viscous properties. is there. That is, by reducing the proportion of elastic properties of the thermoplastic resin, when an external force of rubbing the film is applied, the elastic component that repels to the external force and vibrates is reduced, and the generation of sound is suppressed. Although the index indicating the ratio of elastic property and viscous property is tan δ described above, it is considered effective to reduce unpleasant noise by reducing the ratio of elastic property from macro viewpoint and micro viewpoint There is. The elastic property of the macro viewpoint is the storage elastic modulus (E ') calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention described above. The elastic property of the micro viewpoint is a crystalline component of the resin described later.

Thermoplastic resins are classified into amorphous resins and crystalline resins in terms of crystals. Amorphous resin is a thermoplastic resin in which the molecular chain can not be folded regularly and has no crystal part because the molecular chain has a relatively bulky structure. On the other hand, a crystalline resin is a thermoplastic resin in which molecular chains are regularly folded and has a high-density crystal part inside. However, even though it is a crystalline resin, there is no crystalline resin in which 100% of the molecular chains are crystallized, and both an amorphous part in which the molecular chains are randomly arranged and a crystalline part in which the molecular chains are regularly folded Have.
The amorphous part of the crystalline resin is capable of micro-brown movement in a temperature range above the glass transition temperature (Tg), and is in a state of high mobility. On the other hand, in the crystalline part of the crystalline resin, molecular chains are confined as crystals in a temperature range of not less than the glass transition temperature (Tg) and the melting point (Tm) and become a part having a very high elastic modulus. Therefore, when the degree of crystallization of the crystalline resin is low, the number of crystal parts having a high elastic modulus decreases, so that it is considered that the component that vibrates by repulsion when applying an external force decreases and the noise generated is small. Therefore, the crystal melting enthalpy (ΔHm) is an index of the crystal component ratio in the stretched porous film of the first embodiment of the present invention, and is preferably 10 J / g to 45 J / g.

The storage elastic modulus (E ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film is preferably 8.0 × 10 ⁸ Pa or less at 20 ° C. More preferably, it is 7.0 × 10 ⁸ Pa or less, still more preferably 6.0 × 10 ⁸ Pa or less. When the storage elastic modulus (E ′) is 8.0 × 10 ⁸ Pa or less at 20 ° C., the stretched porous film is excellent in touch such as texture and flexibility. The lower limit is not particularly limited, but from the viewpoint of handling of the stretched porous film, 1.0 × 10 ⁷ Pa or more is preferable at 20 ° C.

The dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention is carried out using a strip-like sample piece cut out with a width of 4 mm and a length of 35 mm at a measurement frequency of 10 Hz. From a measured strain of 0.1%, a distance between chucks of 25 mm, and a measured temperature of -100 ° C., measurement is performed while raising the temperature at a temperature rising rate of 3 ° C./min. At this time, the storage elastic modulus (E ′), loss elastic modulus (E ′ ′), and storage elastic modulus (E ′) and loss elastic modulus (E ′) at each temperature are obtained from the temperature dependence profile of dynamic viscoelasticity obtained. The ratio of E ′ ′) tan δ (= E ′ ′ / E ′) is calculated.
In the dynamic viscoelasticity measurement, the thickness of the sample piece is measured in advance, and the cross-sectional area of the sample piece is calculated by inputting the thickness of the sample piece and the value of the width of the sample piece into the measuring device. It is calculated.
In the stretched porous film of the first embodiment of the present invention, since the pores are generated in the resin composition (Z), when the porous body is measured as it is, the calculated storage elastic modulus (E ′), loss, Errors easily occur in the elastic modulus (E ′ ′) and tan δ. Therefore, in order to obtain the storage elastic modulus (E ′), the loss elastic modulus (E ′ ′) and the tan δ defined in the first embodiment of the present invention, the resin composition (Z Dynamic viscoelasticity measurement is preferably performed on strip-shaped sample pieces cut out in the longitudinal direction (MD): 4 mm and the transverse direction (TD): 35 mm using the unstretched film of. However, after heating the stretched porous film to a temperature above the melting point to melt the film and eliminate the pores, a press sample is prepared, and a strip-like sample piece is cut out from the press sample to perform dynamic viscoelasticity measurement. Also by this, it is possible to calculate the storage elastic modulus (E ′), the loss elastic modulus (E ′ ′), and tan δ defined in the first embodiment of the present invention. In the present invention, any measurement method can be adopted.

Here, for the porosity, a stretched porous film is cut into a size of 50 mm in the longitudinal direction (MD) and 50 mm in the transverse direction (TD), and the specific gravity (W1) of the stretched porous film is measured. Next, the specific gravity (W0) of the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention is measured. In the measurement of the specific gravity (W0) of the resin composition (Z), the unstretched film of the stretched porous film of the first embodiment of the present invention is 50 mm in the longitudinal direction (MD) and 50 mm in the transverse direction (TD). The specific gravity can be measured by cutting out to the size of. In addition, when it is difficult to collect the unstretched sheet, the stretched porous film of the first embodiment of the present invention is heated to the melting point or more to melt the stretched porous film and eliminate the pores, and then a press sample is prepared. The specific gravity can be measured by cutting out the pressed sample into a size of 50 mm in the longitudinal direction (MD) and 50 mm in the transverse direction (TD).
The specific gravity (W1) of the stretched porous film and the specific gravity (W0) of the resin composition (Z) are randomly measured at three points, and the arithmetic mean value is used. From the specific gravity (W1) of the obtained stretched porous film and the specific gravity (W0) of the resin composition (Z), the porosity is calculated from the following equation.
Porosity (%) = [1- (W1 / W0)] × 100

In addition, the crystal melting enthalpy (ΔHm) of the stretched porous film of the first embodiment of the present invention is a differential scanning calorimeter (DSC) of the stretched porous film of the first embodiment of the present invention from -40 ° C to a high temperature The temperature is raised to the holding temperature at a heating rate of 10 ° C./min, held for 1 minute, then lowered from a high temperature holding temperature to -40 ° C. at a cooling rate of 10 ° C./min, held for 1 minute, and further -40 ° C. to the above The crystal melting enthalpy (ΔHm) is calculated from the crystal melting peak area when the temperature is raised again to a high temperature holding temperature at a heating rate of 10 ° C./min. At this time, the high temperature holding temperature can be arbitrarily selected in the range of Tm + 20 ° C. or more and Tm + 150 ° C. or less with respect to the crystal melting peak temperature (Tm) of the thermoplastic resin to be used.
The crystal melting enthalpy (ΔHm) defined in the first embodiment of the present invention is the reheating process even in the case of cold crystallization as seen in semicrystalline resins in the above reheating process. The ΔHm calculated from the crystal melting peak generated in That is, the enthalpy of crystallization (ΔHc) calculated from the exothermic peak area in cold crystallization occurring in the reheating process is not subtracted from ΔHm obtained in the reheating process.
Furthermore, when the stretched porous film of the first embodiment of the present invention is laminated with another layer, if DSC measurement is performed on the laminate as it is, ΔHm derived from the stretched porous film may be estimated to be low. Therefore, when the stretched porous film of the first embodiment of the present invention is a laminate, the stretched porous film of the first embodiment of the present invention can be peeled off, and the ΔHm can be measured for this porous layer. When peeling is difficult, ΔHm of the stretched porous film of the first embodiment of the present invention in the entire laminate is calculated by DSC measurement, and the lamination ratio of the porous layer in the entire laminate is calculated. From the equation, ΔHm defined in the first embodiment of the present invention can be calculated. Although the calculation of the lamination ratio is not particularly limited, it is preferably calculated by cross-sectional observation with an optical microscope, an electron microscope or the like.
ΔHm (J / g) defined in the first embodiment of the present invention = ΔHm (J / g) of the stretched porous film in the whole laminate / lamination ratio (%) / 100 (% of the porous layer in the whole laminate) )

Further, the crystal melting peak temperature (Tm) in the stretched porous film of the first embodiment of the present invention is preferably 70 ° C. or more, more preferably 80 ° C. or more, and 90 ° C. or more More preferable. The number of crystal melting peaks may be one, or two or more. When there are two or more crystal melting peaks, one crystal melting peak temperature (Tm) is preferably 70 ° C. or more. Furthermore, when there are two or more crystal melting peaks, the crystal melting enthalpy (ΔHm) is the sum of the crystal melting enthalpies (ΔHm) calculated from the two or more crystal melting peaks.
In addition, when the thermoplastic resin contained in the resin composition (Z) constituting the stretched porous film of the first embodiment of the present invention is a polyolefin resin, the crystal melting start temperature is 30% of the crystal melting peak temperature (Tm) It melts little by little from temperatures lower than ° C and often shows a broad peak. Therefore, by raising the differential scanning calorimetry (DSC) temperature from -40.degree. C., the baseline can be clarified and the crystal melting enthalpy (.DELTA.Hm) can be calculated more accurately.

The basis weight of the stretched porous film of the first embodiment of the present invention is preferably 10 g / m ² to 50 g / m ² , more preferably 15 g / m ² to 40 g / m ² . When the basis weight is 10 g / m ² or more, mechanical strength such as tensile strength and tear strength can be easily secured sufficiently. In addition, when the basis weight is 50 g / m ² or less, it is easy to obtain a feeling of sufficient lightness.
Here, as the basis weight, a mass (g) of a sample (longitudinal direction (MD): 250 mm, lateral direction (TD): 200 mm) is measured with an electronic balance, and a value obtained by multiplying the value by 20 is taken as basis weight.

The air permeability of the stretched porous film according to the first embodiment of the present invention is preferably 1 second / 100 mL to 5000 seconds / 100 mL, more preferably 10 seconds / 100 mL to 4000 seconds / 100 mL, and 100 seconds. It is more preferable that the ratio is from / 100 mL to 3000 seconds / 100 mL. When the air permeability is 1 second / 100 mL or more, it is easy to ensure sufficient water resistance and liquid permeation resistance. In addition, the air permeability of 5000 seconds / 100 mL or less suggests that it has sufficient communication holes.
Here, the air permeability is the number of seconds in which 100 mL of air passes through the paper, which is measured according to the method defined in JIS P8117: 2009 (Gurley testing machine method). For example, the air permeability measuring device It can be measured using a manufacturing laboratory type air permeability measuring machine EGO1-55). In the present invention, samples are randomly measured at 10 points, and their arithmetic mean value is taken as air permeability.

The moisture permeability of the stretched porous film according to the first embodiment of the present invention is preferably 1000 g / (m ² · 24 h) to 15000 g / (m ² · 24 h), and more preferably 1500 g / (m ² · 24 h) to 12000 g / (M ² · 24 h). The moisture permeability of 15000 g / (m ² · 24 h) or less suggests that it has water resistance. In addition, it is suggested that the holes have sufficient communication because the moisture permeability is 1000 g / (m ² · 24 h) or more.
Here, the moisture permeability conforms to the conditions of JIS Z 0208 (The moisture permeability test method of moisture-proof packaging material (cup method)). Using 15 g of calcium chloride as a hygroscopic agent, the temperature is 40 ° C., and the relative humidity is 90%. The sample is randomly measured at two points and its arithmetic mean value is determined.

7 N / 25 mm or more is preferable and 10 N / 25 mm or more of the tensile breaking strength of the extending | stretching porous film of the 1st Embodiment of this invention of the extending direction is preferable. When the tensile strength at break is 7 N / 25 mm or more, mechanical strength and flexibility sufficient for practical use can be secured. The upper limit is not particularly limited, but in view of stretchability, it is preferably 35 N / 25 mm or less. Here, the tensile breaking strength in the stretching direction is a sample cut out in the stretching direction 100 mm × the stretching direction 25 mm in accordance with JIS K7127, and the tensile speed is 200 m under an environment of 23 ° C. and 50% relative humidity. It is a tensile breaking strength at the time of breaking using a triple tension tester under the condition of 50 min. In the present invention, an arithmetic mean value of tensile strength at break calculated by performing measurement three times is used.

The tensile breaking elongation in the stretching direction in the stretched porous film of the first embodiment of the present invention is preferably 40% to 400%, and more preferably 100% to 300%. When the stretched porous film of the present invention is used as a diaper for diapers and a hygienic product such as a moisture-permeable back sheet such as a menstrual treatment product with a tensile elongation at break of 40% or more, the touch is good and the excellent feel is excellent Is obtained. In addition, when the tensile elongation at break is 400% or less, it has appropriate rigidity and tensile strength, is excellent in mechanical properties, and has low elongation and distortion of film during printing, slitting, and winding processing, and excellent mechanical suitability in a production line Is obtained.
Here, the tensile elongation at break in the stretching direction is prepared according to JIS K7127 by preparing a sample cut out in a stretching direction of 100 mm × 25 mm perpendicular to the stretching direction, under an environment of 23 ° C. and a relative humidity of 50%. It is a tensile breaking elongation at the time of breaking using a triple tension tester under the conditions of 200 m / min and a distance between chucks of 50 mm. In the present invention, an arithmetic mean value of tensile elongation at break calculated by performing measurement three times is used.

The heat shrinkage rate in the stretching direction when the stretched porous film of the first embodiment of the present invention is heated at 60 ° C. for 1 hour is preferably less than 5.0%, and more preferably less than 4.0%. preferable. When the heat shrinkage rate in the stretching direction when heated at 60 ° C. for 1 hour is less than 5.0%, blocking and winding tightness when the roll-shaped sample of the stretched porous film is stored over time are preferable.
Here, the thermal contraction rate is left standing and heated for 1 hour in a convection oven in which the temperature in the tank is set to 60 ° C., for which the sample cut out in the stretching direction of 200 mm × 10 mm perpendicular to the stretching direction is set. Thereafter, the length L (mm) in the stretching direction is measured, which is a value calculated by the formula “(200-L) / 200 × 100 (%)”. In the present invention, the measurement is made three times to obtain the arithmetic mean value of the thermal contraction rate calculated.

The total light transmittance of the stretched porous film of the first embodiment of the present invention is preferably 18% to 60%. When using the stretched porous film of the first embodiment of the present invention for sanitary goods such as back sheets for moisture-permeable waterproofs such as disposable diapers by having a total light transmittance of 18% or more, an indicator drug which indicates that urination has occurred Even if it applies, it can recognize. In addition, the film is white and rich in hiding power because the total light transmittance is 60% or less.
Here, the total light transmittance is obtained by randomly measuring five points using a haze meter in accordance with JIS K7361 and calculating its arithmetic mean value.

Hereinafter, another embodiment of the film of the present invention will be described.

1-2. Stretched porous film (second embodiment of the present invention)
The stretched porous film of the second embodiment of the present invention is a stretched porous film composed of a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A), and the dynamic film of the resin composition (Z) (= E ′ ′ / E ′), which is the ratio of storage elastic modulus (E ′) to loss elastic modulus (E ′ ′) calculated from dynamic viscoelasticity measurement, is 0.100 or more at −20 ° C., It is a stretched porous film having a crystal melting peak (Pm1) at 140 ° C. to 200 ° C.

The stretched porous film of the second embodiment of the present invention comprises a resin composition (Z) containing 25% by mass to 54% by mass of a thermoplastic resin and 46% by mass to 75% by mass of an inorganic filler (A). Is preferred. Therefore, the stretched porous film of the second embodiment of the present invention more preferably is a resin composition containing 25% by mass to 54% by mass of a thermoplastic resin and 46% by mass to 75% by mass of an inorganic filler (A). A stretched porous film comprising (Z), which is a ratio of a storage elastic modulus (E ′) to a loss elastic modulus (E ′ ′) calculated from measurement of dynamic viscoelasticity of the resin composition (Z), tan δ (= E ′ ′ / E ′) is 0.100 or more at −20 ° C., and is a stretched porous film having a crystal melting peak (Pm1) at 140 ° C. to 200 ° C.

In the stretched porous film of the second embodiment of the present invention, the storage elastic modulus (E ') and the loss elastic modulus (E') calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film It is important that tan δ (= E ′ ′ / E ′) which is the ratio of ') is 0.100 or more at -20 ° C., preferably 0.110 or more, and 0.120 or more Is more preferably 0.130 or more. The upper limit of tan δ of the resin composition (Z) constituting the stretched porous film is not particularly limited, but is preferably 1.000 or less at -20 ° C. from the viewpoint of dimensional stability. The sound absorption coefficient (vibration attenuation factor) for suppressing the unpleasant sound generated when the film is rubbed, as described later, when tan δ (= E ′ ′ / E ′) is 0.100 or more at −20 ° C. The film is excellent in touch such as flexibility and texture.

The tan δ is preferably 0.100 or more at -20 ° C to -10 ° C, more preferably 0.100 or more at -20 ° C to 0 ° C, and 0.100 at -30 ° C to 0 ° C. It is more preferable that the above is more preferably 0.100 or more at -30 ° C to 10 ° C, still more preferably 0.100 or more at -30 ° C to 20 ° C. Most preferably, it is 0.100 or more in ° C. As will be described later, the temperature range in which tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention is 0.100 or more is broadened In addition, unpleasant noises of various frequencies can be suppressed.

Furthermore, the porosity of the stretched porous film of the second embodiment of the present invention is preferably 15% to 80%. The porosity is more preferably 20% to 80%, and still more preferably 25% to 80%.
When the porosity is 15% or more, as described later, the energy loss opportunity of sound propagating in the pores of the stretched porous film increases, and unpleasant noise can be sufficiently suppressed. In addition, when the porosity is 80% or less, it is possible to secure a film strength that can be practically used, and further, the waterproofness is sufficient, and it becomes difficult to cause the leakage of the liquid material in contact.

Sound is an oscillatory wave of air that occurs when an object moves or rubs. When a sound collides with an object as an incident sound, the incident sound is classified into three sounds of a transmitted sound transmitted through the object, a reflected sound reflected the object, and an absorbed sound absorbed by the object from the relation of energy conservation law. It is disassembled. That is, when an incident sound collides with an object, if the ratio of absorbed sound absorbed by the object is large, the object is considered to be an object having a high sound absorption coefficient.
The stretched porous film of the second embodiment of the present invention is a film having a void communicated with the inside of the resin composition (Z). That is, when the sound is propagated in the stretched porous film of the second embodiment of the present invention, the sound is formed by vibrating the resin composition (Z) forming the solid portion as a film and propagating inside the film It shows two ways of transmission with the sound that propagates through the air gap that has communicated. Therefore, to suppress the sound, it is necessary to consider the suppression of the sound that propagates by vibrating the resin composition (Z), and the suppression of the sound that propagates through the open space.

In the stretched porous film of the second embodiment of the present invention, it is considered that damping of the vibration source of sound or the medium is effective for suppressing the sound which propagates by vibrating the resin composition (Z). In a viscoelastic body such as a resin, a sound absorbing effect can be obtained by losing the energy of vibration to thermal energy. Therefore, tan δ, which is the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′), is considered to be a necessary element to exhibit this sound absorption effect. Therefore, in the second embodiment of the present invention, it is preferable that the peak value of tan δ of the resin composition (Z) constituting the stretched porous film be larger.
Further, the peak position of tan δ of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention relates to the attenuation at the temperature at which the sound is generated, and from the viewpoint of the temperature-time conversion law. It also relates to the attenuation to the frequency. Therefore, it is preferable that the peak width of tan δ be wider in order to absorb or not generate unpleasant sounds having various frequencies.
Therefore, the storage elastic modulus (E ′) and the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention It is important that tan δ (= E ′ ′ / E ′), which is a ratio of, is not less than 0.100 at −20 ° C. in order to suppress the generation of unpleasant noise generated when the film is rubbed. As described above, it is preferable that the temperature range in which tan δ is 0.100 or more is broadened because unpleasant noises of various frequencies can be suppressed.

In addition, the porosity of the porous film is also considered to contribute to the suppression of the propagating sound. By increasing the porosity, the number of collisions between the sound propagating in the air and the object increases, so it is considered that the sound suppression effect can be obtained which propagates the communicated air gap formed inside the film. There is.
Therefore, it is preferable that the porosity of the stretched porous film is 15% or more in order to increase the energy loss opportunity of sound propagating in the pores of the film.

It is important that the stretched porous film of the second embodiment of the present invention has a crystal melting peak (Pm1) at 140 ° C. to 200 ° C. The crystal melting peak (Pm1) is preferably at 150 ° C. to 190 ° C., and more preferably at 160 ° C. to 180 ° C. Having a crystal melting peak (Pm1) at 140 ° C. or higher makes it possible to impart sufficient heat resistance when bonding and laminating the stretched porous film with other members, which is important. Further, by having the crystal melting peak (Pm1) at 200 ° C. or less, there is no need to extremely increase the extrusion temperature in forming a stretched porous film, and therefore it is difficult to generate resin degradation products and the like, productivity is improved. Because it is preferable.
In order to have the crystal melting peak (Pm1), the thermoplastic resin having a melting point of 140 ° C. to 200 ° C. is contained in the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention. Can be adjusted to have the crystal melting peak (Pm1) in the above range.

In the stretched porous film of the second embodiment of the present invention, the crystal melting enthalpy (ΔHm1) calculated from the crystal melting peak (Pm1) is preferably 1 J / g to 10 J / g. The crystal melting enthalpy (ΔHm1) is more preferably 1 J / g to 8 J / g, and still more preferably 2 J / g to 6 J / g. When the crystal melting enthalpy (ΔHm1) is 1 J / g or more, it is preferable because it has a sufficient crystal component to impart heat resistance to the stretched porous film. Moreover, generation | occurrence | production of the unpleasant noise mentioned later can be suppressed because the said crystal melting enthalpy ((DELTA) Hm1) is 10 J / g or less.
In the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention, the crystal melting enthalpy (ΔHm1) can be reduced by adjusting the mixing ratio of the thermoplastic resin having a melting point of 140 ° C. to 200 ° C. It can adjust to the said range.

The stretched porous film of the second embodiment of the present invention preferably further has a crystal melting peak (Pm2) at 30 ° C to 130 ° C. The crystal melting enthalpy (ΔHm2) calculated from the crystal melting peak (Pm2) is preferably 10 J / g to 45 J / g. The crystal melting enthalpy (ΔHm2) is more preferably 12 J / g to 43 J / g, and still more preferably 14 J / g to 41 J / g. When the crystal melting enthalpy (ΔHm2) is 10 J / g or more, the heat resistance and the dimensional stability of the stretched porous film can be secured. Moreover, generation | occurrence | production of the unpleasant noise mentioned later can be suppressed because the said crystal melting enthalpy ((DELTA) Hm2) becomes 45 J / g or less.
In order to have the crystalline melting peak (Pm2), the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention contains a thermoplastic resin having a melting point of 30 ° C to 130 ° C, By adjusting the mixing ratio, the crystal melting peak (Pm2) and the crystal melting enthalpy (ΔHm2) can be adjusted to the above ranges.

As a method of suppressing the unpleasant sound generated when rubbing the stretched porous film, it is considered effective to suppress the generation of the sound from the sound source as well as suppressing the above-mentioned propagation sound. The generation of sound is the vibration of the elastic body, and no sound is generated unless there is something that causes the vibration (= sound source).
Focusing on the thermoplastic resin contained in the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention, the thermoplastic resin is a viscoelastic body having both elastic properties and viscous properties. It is. That is, by reducing the proportion of elastic properties of the thermoplastic resin, when an external force of rubbing the film is applied, the elastic component that repels to the external force and vibrates is reduced, and the generation of sound is suppressed. Although the index indicating the ratio of elastic property and viscous property is tan δ described above, it is considered effective to reduce unpleasant noise by reducing the ratio of elastic property from macro viewpoint and micro viewpoint There is. The elastic property of the macro viewpoint is the storage elastic modulus (E ') calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention described above. The elastic property of the micro viewpoint is a crystalline component of the resin described later.

First, from the viewpoint of reducing the elastic properties of the macro viewpoint, the storage elastic modulus (E) calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention (E) ') Is preferably 8.0 × 10 ⁸ Pa or less at 20 ° C. More preferably, it is 7.0 × 10 ⁸ Pa or less, still more preferably 6.0 × 10 ⁸ Pa or less. When the storage elastic modulus (E ′) is 8.0 × 10 ⁸ Pa or less at 20 ° C., the stretched porous film is excellent in touch such as texture and flexibility, and suppresses generation of unpleasant noise. It is preferable because The lower limit is not particularly limited, but from the viewpoint of handling of the stretched porous film, 1.0 × 10 ⁷ Pa or more is preferable at 20 ° C.

The dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film according to the second embodiment of the present invention is performed on a strip-like sample piece cut out with a width of 4 mm and a length of 35 mm at a measurement frequency of 10 Hz. From a measured strain of 0.1%, a distance between chucks of 25 mm, and a measured temperature of -100 ° C., measurement is performed while raising the temperature at a temperature rising rate of 3 ° C./min. At this time, the storage elastic modulus (E ′), loss elastic modulus (E ′ ′), and storage elastic modulus (E ′) and loss elastic modulus (E ′) at each temperature are obtained from the temperature dependence profile of dynamic viscoelasticity obtained. The ratio of E ′ ′) tan δ (= E ′ ′ / E ′) is calculated.
In the dynamic viscoelasticity measurement, the thickness of the sample piece is measured in advance, and the cross-sectional area of the sample piece is calculated by inputting the thickness of the sample piece and the value of the width of the sample piece into the measuring device. It is calculated.
In the stretched porous film of the second embodiment of the present invention, since the pores are generated in the resin composition (Z), when the porous body is measured as it is, the calculated storage elastic modulus (E ′), loss, Errors easily occur in the elastic modulus (E ′ ′) and tan δ. Therefore, in order to obtain the storage elastic modulus (E ′), loss elastic modulus (E ′ ′), and tan δ specified in the second embodiment of the present invention, a resin composition (Z It is preferable to perform a dynamic viscoelasticity measurement about the strip-like sample piece cut out by MD: 4 mm and TD: 35 mm using the unstretched film of 2.). However, after heating the stretched porous film to a temperature above the melting point to melt the film and eliminate the pores, a press sample is prepared, and a strip-like sample piece is cut out from the press sample to perform dynamic viscoelasticity measurement. Also by this, it is possible to calculate the storage elastic modulus (E ′), loss elastic modulus (E ′ ′) and tan δ defined in the second embodiment of the present invention. In the present invention, any measurement method can be adopted.

Next, as an elastic property of the micro viewpoint, the crystalline component of the resin is considered. Thermoplastic resins are classified into amorphous resins and crystalline resins in terms of crystals. Amorphous resin is a thermoplastic resin in which the molecular chain can not be folded regularly and has no crystal part because the molecular chain has a relatively bulky structure. On the other hand, a crystalline resin is a thermoplastic resin in which molecular chains are regularly folded and has a high-density crystal part inside. However, even though it is a crystalline resin, there is no crystalline resin in which 100% of the molecular chains are crystallized, and both an amorphous part in which the molecular chains are randomly arranged and a crystalline part in which the molecular chains are regularly folded Have.
The amorphous part of the crystalline resin is capable of micro-brown movement in a temperature range above the glass transition temperature, and is in a state of high mobility. On the other hand, in the crystalline part of the crystalline resin, molecular chains are confined as crystals in a temperature range of not less than the glass transition temperature and not more than the melting point, and it becomes a part having a very high elastic modulus. Therefore, when the degree of crystallization of the crystalline resin is low, the number of crystal parts having a high elastic modulus decreases, so that it is considered that the component that vibrates by repulsion when applying an external force decreases and the noise generated is small.
Accordingly, the crystal melting enthalpy is an index of the crystal component ratio in the stretched porous film of the second embodiment of the present invention, and the crystal melting enthalpy (ΔHm1) is preferably 1 J / g to 10 J / g. The crystal melting enthalpy (ΔHm2) is preferably 10 J / g to 45 J / g.

The crystalline melting peak (Pm) and the peak temperature (Tm) of the stretched porous film of the second embodiment of the present invention are the differential scanning calorimeter (DSC), and the stretched of the second embodiment of the present invention The porous film is heated from -40 ° C to a high temperature holding temperature at a heating rate of 10 ° C / min, held for 1 minute, then lowered from a high temperature holding temperature to -40 ° C at a cooling rate of 10 ° C / min, held for 1 minute Crystal melting peak (Pm) which appears when the temperature is raised again from −40 ° C. to the above-mentioned high temperature holding temperature at a heating rate of 10 ° C./min, and the temperature (Tm) showing the peak.
Further, the crystal melting enthalpy (ΔHm) is calculated from the peak area of the crystal melting peak (Pm) that appears when the temperature is raised again. At this time, the high temperature holding temperature can be arbitrarily selected in the range of Tm + 20 ° C. or more and Tm + 150 ° C. or less with respect to the highest crystal melting peak temperature (Tm) of the thermoplastic resin to be used.
In the second embodiment of the present invention, the crystal melting enthalpy (ΔHm) occurs in the reheating process, even in the case of cold crystallization as seen in a semicrystalline resin in the reheating process. The ΔHm calculated from the crystal melting peak is applied. That is, the crystallization enthalpy (ΔHc) calculated from the exothermic peak area in cold crystallization occurring in the reheating process is not subtracted from ΔHm obtained in the reheating process.

Furthermore, when the stretched porous film of the second embodiment of the present invention is laminated with another layer, when the DSC measurement is performed on the laminate as it is, ΔHm derived from the stretched porous film may be estimated to be low. Therefore, when the stretched porous film of the second embodiment of the present invention is a laminate, the stretched porous film of the second embodiment of the present invention can be peeled off, and ΔHm can be measured for this porous layer. When peeling is difficult, while calculating ΔHm of the stretched porous film of the second embodiment of the present invention in the entire laminate by DSC measurement, the lamination ratio of the porous layer in the entire laminate is calculated, and the following From the calculation formula, ΔHm in the second embodiment of the present invention can be calculated. Although the calculation of the lamination ratio is not particularly limited, it is preferably calculated by cross-sectional observation with an optical microscope, an electron microscope or the like.
In the second embodiment of the present invention, ΔHm (J / g) = ΔHm (J / g) of the stretched porous film in the whole laminate / lamination ratio (%) / 100 (%) of the porous layer in the whole laminate

Moreover, although it is important that the crystal melting peak (Pm1) in the stretched porous film of the second embodiment of the present invention has at 140 ° C. to 200 ° C., at least one crystal melting peak at 140 ° C. to 200 ° C. As long as it has, it may be two or more. When two or more crystal melting peaks exist at 140 ° C. to 200 ° C., the crystal melting enthalpy (ΔHm1) is the sum of crystal melting enthalpies calculated from two or more crystal melting peaks.

The crystal melting peak (Pm2) is also preferably at least one crystal melting peak at 30 ° C. to 130 ° C., but may be two or more. In addition, when there are two or more crystal melting peaks at 30 ° C. to 130 ° C., the crystal melting enthalpy (ΔHm 2) is a total value of crystal melting enthalpies calculated from two or more crystal melting peaks.

In addition, when the thermoplastic resin contained in the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention is a polyolefin resin, the crystal melting start temperature is more than 30 from the crystal melting peak temperature (Tm) It melts little by little from temperatures lower than ° C and often shows a broad peak. Therefore, by raising the differential scanning calorimetry (DSC) temperature from -40.degree. C., the baseline can be clarified and the crystal melting enthalpy (.DELTA.Hm) can be calculated more accurately.

Summarizing the above, the second embodiment of the present invention relates to the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z). A sound absorption coefficient to suppress unpleasant noise generated when the film rubs, as well as excellent in touch such as flexibility and texture by setting the temperature at which certain tan δ and crystal melting peak (Pm1) occur to a suitable range While improving the (vibration attenuation rate), the heat resistance required for the stretched porous film can be compatible.

The porosity of the stretched porous film according to the second embodiment of the present invention is as follows: the stretched porous film is cut into a size of 50 mm in the longitudinal direction (MD) and 50 mm in the transverse direction (TD); Measure W1). Next, the specific gravity (W0) of the resin composition (Z) constituting the stretched porous film of the second embodiment of the present invention is measured. In the measurement of the specific gravity (W0) of the resin composition (Z), the unstretched film of the stretched porous film of the second embodiment of the present invention is a longitudinal direction (MD): 50 mm, a transverse direction (TD): 50 mm The specific gravity can be measured by cutting out to the size of. In addition, when it is difficult to collect an unstretched sheet, the stretched porous film of the second embodiment of the present invention is heated to a temperature higher than the melting point to melt the stretched porous film and eliminate pores, and then prepare a press sample. The specific gravity can be measured by cutting out the pressed sample into a size of 50 mm in the longitudinal direction (MD) and 50 mm in the transverse direction (TD).
The specific gravity (W1) of the stretched porous film and the specific gravity (W0) of the resin composition (Z) are randomly measured at three points, and the arithmetic mean value is used. From the specific gravity (W1) of the obtained stretched porous film and the specific gravity (W0) of the resin composition (Z), the porosity is calculated from the following equation.
Porosity (%) = [1- (W1 / W0)] × 100

The basis weight of the stretched porous film of the second embodiment of the present invention is preferably 10 g / m ² to 50 g / m ² , more preferably 12 g / m ² to 40 g / m ² . When the basis weight is 10 g / m ² or more, mechanical strength such as tensile strength and tear strength can be easily secured sufficiently. In addition, when the basis weight is 50 g / m ² or less, it is easy to obtain a feeling of sufficient lightness.
Here, as the basis weight, a mass (g) of a sample (longitudinal direction (MD): 250 mm, lateral direction (TD): 200 mm) is measured with an electronic balance, and a value obtained by multiplying the value by 20 is taken as basis weight.

The air permeability of the stretched porous film of the second embodiment of the present invention is preferably 1 second / 100 mL to 5000 seconds / 100 mL, more preferably 10 seconds / 100 mL to 4000 seconds / 100 mL, and 100 seconds. It is more preferable that the ratio is from / 100 mL to 3000 seconds / 100 mL. When the air permeability is 1 second / 100 mL or more, it is easy to ensure sufficient water resistance and liquid permeation resistance. In addition, the air permeability of 5000 seconds / 100 mL or less suggests that it has sufficient communication holes.
Here, the air permeability is the number of seconds in which 100 mL of air passes through the paper, which is measured according to the method defined in JIS P8117: 2009 (Gurley testing machine method). For example, the air permeability measuring device It can be measured using a manufacturing laboratory type air permeability measuring machine EGO1-55). In the present invention, samples are randomly measured at 10 points, and their arithmetic mean value is taken as air permeability.

The moisture permeability of the stretched porous film according to the second embodiment of the present invention is preferably 1000 g / (m ² · 24 h) to 15000 g / (m ² · 24 h), more preferably 1500 g / (m ² · 24 h) to 1 2000 g / (M ² · 24 h). The moisture permeability of 15000 g / (m ² · 24 h) or less suggests that it has water resistance. In addition, it is suggested that the holes have sufficient communication because the moisture permeability is 1000 g / (m ² · 24 h) or more.
Here, the moisture permeability conforms to the conditions of JIS Z 0208 (The moisture permeability test method of moisture-proof packaging material (cup method)). Using 15 g of calcium chloride as a hygroscopic agent, the temperature is 40 ° C., and the relative humidity is 90%. The sample is randomly measured at two points and its arithmetic mean value is determined.

7 N / 25 mm or more is preferable and 10 N / 25 mm or more of the tensile breaking strength of the extending | stretching porous film of the 2nd Embodiment of this invention of the extending direction is preferable. When the tensile strength at break is 7 N / 25 mm or more, mechanical strength and flexibility sufficient for practical use can be secured. The upper limit is not particularly limited, but in view of stretchability, it is preferably 35 N / 25 mm or less. Here, the tensile breaking strength in the stretching direction is a sample cut out in the stretching direction 100 mm × the stretching direction 25 mm in accordance with JIS K7127, and the tensile speed is 200 m under an environment of 23 ° C. and 50% relative humidity. It is a tensile breaking strength at the time of breaking using a triple tension tester under the condition of 50 min. In the present invention, an arithmetic mean value of tensile strength at break calculated by performing measurement three times is used.

The tensile breaking elongation in the stretching direction in the stretched porous film of the second embodiment of the present invention is preferably 40% to 400%, and more preferably 80% to 300%. When using the stretched porous film of the second embodiment of the present invention as a tensile diaper with a tensile elongation at break of 40% or more for sanitary goods such as disposable diapers and back sheets for moisture-permeable waterproofs such as sanitary products, the touch is good. You get an excellent feeling of comfort. In addition, when the tensile elongation at break is 400% or less, it has appropriate rigidity and tensile strength, is excellent in mechanical properties, and has low elongation and distortion of film during printing, slitting, and winding processing, and excellent mechanical suitability in a production line Is obtained.
Here, the tensile elongation at break in the stretching direction is prepared according to JIS K7127 by preparing a sample cut out in a stretching direction of 100 mm × 25 mm perpendicular to the stretching direction, under an environment of 23 ° C. and a relative humidity of 50%. It is a tensile breaking elongation at the time of breaking using a triple tension tester under the conditions of 200 m / min and a distance between chucks of 50 mm. In the present invention, an arithmetic mean value of tensile elongation at break calculated by performing measurement three times is used.

The total light transmittance of the stretched porous film of the second embodiment of the present invention is preferably 18% to 60%. An indicator medicine which indicates that urination has occurred when the stretched porous film of the second embodiment of the present invention is used for sanitary goods such as back sheets for moisture-permeable waterproofs such as paper diapers by having a total light transmittance of 18% or more Even if it applies, it can recognize. In addition, the film is white and rich in hiding power because the total light transmittance is 60% or less.
Here, the total light transmittance is obtained by randomly measuring five points using a haze meter in accordance with JIS K7361 and calculating its arithmetic mean value.

120 degreeC or more is preferable, as for the film-breaking heat resistance temperature in the stretched porous film of the 2nd Embodiment of this invention, 140 degreeC or more is more preferable, and 160 degreeC or more is still more preferable. When bonding and laminating the stretched porous film of the second embodiment of the present invention to other members with a film rupture heat resistance temperature of 120 ° C. or higher, the film does not break by heat such as a hot melt adhesive. It can be judged that the heat resistance necessary for the stretched porous film is imparted.
Here, the heat resistance temperature of the film is held by holding a sample (100 mm × 100 mm) with two stainless steel plates (100 mm × 100 mm × 2 mm (thickness)) obtained by punching the center into a 5050 mm circle and fixing the four sides with clips. After standing for 2 minutes in a convection oven with a temperature of 120 ° C in the bath and heating, the sample of the circular punching point of the stainless steel sheet melts, and the appearance of holes is visually judged, and tears and holes The one with no opening is made to have a rupture heat resistance temperature of 120 ° C. or more. In addition, the temperature in the tank is changed to 140 ° C. and 160 ° C., and when the same evaluation is performed, those having no tear or hole opening are made to have a rupture heat resistance temperature of 140 ° C. or more and 160 ° C. or more.

Hereinafter, after demonstrating the resin composition (Z) which comprises the stretched porous film of this invention, the manufacturing method of a stretched porous film is demonstrated. The “oriented porous film of the present invention” refers to the above-mentioned “oriented porous film of the first embodiment of the present invention” and “oriented porous film of the second embodiment of the present invention”.

2. Resin composition (Z) constituting stretched porous film
It is important that the stretched porous film of the present invention comprises a resin composition (Z) containing 25% by mass to 54% by mass of a thermoplastic resin and 46% by mass to 75% by mass of an inorganic filler (A).

2-1. Inorganic filler (A)
Examples of the inorganic filler (A) include fine particles and minerals of calcium carbonate, calcium sulfate, barium carbonate, barium sulfate, titanium oxide, talc, clay, kaolinite, montmorillonite etc. Calcium carbonate and barium sulfate can be suitably used because of advantages such as expression, high versatility, low price, and abundant brand name.

The average particle diameter of the inorganic filler (A) is preferably 0.1 to 10 μm, more preferably 0.3 to 5 μm, and still more preferably 0.5 to 3 μm. If the average particle size is 0.1 μm or more, dispersion failure and secondary aggregation of the inorganic filler (A) are suppressed, and the resin can be uniformly dispersed in the resin composition (Z), which is preferable. On the other hand, when the average particle diameter is 10 μm or less, generation of large voids can be suppressed at the time of film thinning, and sufficient strength and water resistance can be secured for the film. Further, for the purpose of improving the dispersibility and mixing property with the resin, it is preferable to previously coat the inorganic filler with a fatty acid, fatty acid ester or the like to make the surface of the inorganic filler conformable to the resin. In the inorganic filler (A) to be treated, a surface-treated inorganic filler can be used.

2-2. Thermoplastic resin As the thermoplastic resin, polyolefin resin, polystyrene resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, chlorinated polyethylene resin, polyester resin, polycarbonate resin, polyamide resin Resin, ethylene / vinyl alcohol copolymer, ethylene / vinyl acetate copolymer, polymethylpentene resin, polyvinyl alcohol resin, cyclic olefin resin, polylactic acid resin, polybutylene succinate resin, polyacrylonitrile Resin, polyethylene oxide resin, cellulose resin, polyimide resin, polyurethane resin, polyphenylene sulfide resin, polyphenylene ether resin, polyvinyl acetal resin, polybutadiene resin, polybutene resin Fat, polyamide imide resin, polyamide bis maleimide resin, poly arylate resin, polyether imide resin, polyether ether ketone resin, polyether ketone resin, polyether sulfone resin, poly ketone resin, poly sulfone resin And aramid resins, fluorine resins, polyacetal resins and the like. Among them, a polyolefin resin is preferable as the thermoplastic resin from the viewpoints of flexibility, heat resistance, formation of communicating holes, environmental hygiene, odor and the like.
The thermoplastic resin may be of one type or of two or more types. When the said thermoplastic resin is comprised by 2 or more types, the sum total turns into a mass of the said thermoplastic resin, and the mass ratio of the said thermoplastic resin in resin composition (Z) is calculated.

The polyolefin resin is a resin containing an olefin monomer as a main monomer component. The main monomer component refers to a monomer component that occupies 50% by mole or more and 100% by mole or less in the resin. Examples of olefin monomers include ethylene, propylene, α-olefins such as 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene, dienes, isoprenes, butylenes, butadienes and the like. Or a multicomponent copolymer obtained by copolymerizing two or more of them. In addition, vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, glycidyl (meth) acrylic acid, vinyl alcohol, ethylene glycol, maleic anhydride, styrene, diene, cyclic olefin may be copolymerized. Among them, ethylene homopolymer, branched low density polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, styrene / ethylene / propylene copolymer, styrene from the viewpoint of imparting flexibility and texture / Ethylene / butylene copolymer is preferred.

When the thermoplastic resin is a polyolefin resin, it may be one type or two or more types as long as it is a resin containing an olefin monomer as a main monomer component. When the said polyolefin resin is comprised by 2 or more types, the sum total becomes the mass of the said polyolefin resin.

When the thermoplastic resin is a polyolefin resin, the density of the polyolefin resin is preferably 0.850 g / cm ³ or more and 0.940 g / cm ³ or less. In addition, as the polyolefin resin, polyethylene resin (B) having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, and a density of 0.850 g / cm ³ or more and 0.910 g / cm ^{3 or} less It is preferable to have the soft polyolefin resin (C) of

2-2-1. Polyethylene resin (B)
The polyethylene resin (B) is a resin having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less and ethylene as a main monomer component. The main monomer component refers to a monomer component that occupies 50% by mole or more and 100% by mole or less in the resin. Therefore, the polyethylene-based resin (B) may be an ethylene homopolymer, or may be a copolymer containing ethylene as a main monomer component and containing other monomers. Examples of the copolymer include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene copolymer, ethylene / 1. Ethylene / α-olefin copolymers such as -octene copolymer, and also ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) acrylic acid ester copolymer, Ethylene / glycidyl (meth) acrylate, ethylene / vinyl alcohol copolymer, ethylene / ethylene glycol copolymer, ethylene / maleic anhydride copolymer, ethylene / styrene copolymer, ethylene / diene copolymer, ethylene / ethylene copolymer A cyclic olefin copolymer etc. are mentioned. A multicomponent copolymer containing two or more of the above-mentioned monomer components, such as an ethylene / propylene / 1-butene copolymer, may be used.
Among these, ethylene homopolymers and ethylene / α-olefin copolymers are preferable from the viewpoint of heat shrinkage resistance and dimensional stability.

The polyethylene resin (B) may have a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, and may be one type as long as it is a resin containing ethylene as a main monomer component. It may be two or more types. When the said polyethylene-type resin (B) is comprised by 2 or more types, the sum total becomes the mass of the said polyethylene-type resin (B).
Permeability, moisture permeability, heat shrinkage resistance, dimensional stability, liquid leakage resistance of the stretched porous film by containing the polyethylene resin (B) having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less , Concealment, appearance, etc. can be satisfied. The density of the polyethylene resin (B) is more preferably at most 0.910 g / cm ³ or more 0.937 g / cm ^3, not more than 0.910 g / cm ³ or more 0.935 g / cm ^3, especially preferable. Here, the density is a density measured by the pycnometer method (JIS K7112 B method). Moreover, it is a value when it measures similarly about the density of resin mentioned later.

The polyethylene resin (B) may be linear or branched. The method for producing the polyethylene-based resin (B) is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst represented by a Ziegler-Natta type catalyst, a metallocene-based catalyst The polymerization method etc. which used the single site catalyst represented by these are mentioned.

It is preferable that at least one kind of the polyethylene resin (B) is branched low density polyethylene. When at least one type of the polyethylene-based resin (B) is a branched low density polyethylene, the melt tension of the resin composition (Z) is increased, and the molding processability is preferably improved. In addition, branched low density polyethylene has a value of tan δ (= E ′ ′ / E ′) which is a ratio of storage elastic modulus (E ′) to loss elastic modulus (E ′ ′) calculated from dynamic viscoelasticity measurement. However, since it exhibits a large value at 0 to 30 ° C., it is preferable that at least one of the polyethylene resins (B) is a branched low density polyethylene.

The melting point of the polyethylene resin (B) is preferably 110 to 135 ° C., and more preferably 110 to 130 ° C. If the melting point of the polyethylene-based resin (B) is 110 to 135 ° C., it is preferable because the heat shrinkage resistance and the dimensional stability of the stretched porous film can be improved.
Here, the melting point is about 10 mg of resin heated to -40 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC), and maintained at 200 ° C. for 1 minute, then a cooling rate 10 It is a crystal melting peak temperature (Tm) (° C.) determined from a thermogram measured when the temperature is lowered to −40 ° C. at a rate of 10 ° C./min at a heating rate of 10 ° C./min. Moreover, it is a value when it measures similarly about melting | fusing point of resin mentioned later.

The melt flow rate (MFR) of the polyethylene resin (B) is preferably 0.1 to 20 g / 10 minutes, and more preferably 0.5 to 10 g / 10 minutes. By setting the MFR to 0.1 g / 10 min or more, the formability of the stretched porous film can be sufficiently maintained, which is preferable. Moreover, since the intensity | strength of a stretched porous film can fully be hold | maintained by setting it as 20 g / 10 minutes or less, it is preferable.
Here, MFR is a value measured based on JISK7219, and the measurement conditions are 190 ° C and 2.16 kg load.

2-2-2. Soft polyolefin resin (C)
The soft polyolefin resin (C) is a resin having a density of 0.850 g / cm ³ or more and less than 0.910 g / cm ³ and containing an olefin monomer as a main monomer component. The main monomer component refers to a monomer component that occupies 50% by mole or more and 100% by mole or less in the resin. Examples of olefin monomers include ethylene, propylene, α-olefins such as 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene, dienes, isoprenes, butylenes, butadienes and the like. Or a multicomponent copolymer obtained by copolymerizing two or more of them. In addition, vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, glycidyl (meth) acrylic acid, vinyl alcohol, ethylene glycol, maleic anhydride, styrene, diene, cyclic olefin may be copolymerized. Among them, ethylene homopolymer, branched low density polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, styrene / ethylene / propylene copolymer, styrene from the viewpoint of imparting flexibility and texture / Ethylene / butylene copolymer is preferred.

The soft polyolefin resin (C) has a density of not less than 0.850 g / cm ^{3 and not} more than 0.910 g / cm ³ , and even if it is a resin having an olefin monomer as a main monomer component, It may be two or more types. When the said soft polyolefin resin (C) is comprised by 2 or more types, the sum total becomes the mass of the said soft polyolefin resin (C). By containing the soft polyolefin resin (C) having a density of 0.850 g / cm ³ or more and less than 0.910 g / cm ³ , the flexibility and the texture of the stretched porous film can be improved, and the touch satisfaction can be improved. Further, the density of the flexible polyolefin resin (C) is preferably less than 0.855 g / cm ³ or more 0.910 g / cm ^3, less than 0.860 g / cm ³ or more 0.910 g / cm ³ Is more preferred.

The soft polyolefin resin (C) preferably has a melt flow rate (MFR) of 0.1 to 20 g / 10 min, and more preferably 0.5 to 10 g / 10 min. By setting the MFR to 0.1 g / 10 min or more, the formability of the stretched porous film can be sufficiently maintained, which is preferable. Moreover, since the intensity | strength of a stretched porous film can fully be hold | maintained by setting it as 20 g / 10 minutes or less, it is preferable.

Further, tan δ (= E ′ ′ / E ′), which is the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the soft polyolefin resin (C). The peak of is preferably in the range of -50 to 50.degree. When the peak of tan δ of the soft polyolefin resin (C) is in the range of −50 to 50 ° C., this is preferable because it contributes to suppression of unpleasant noise such as rattle and snail.

Further, tan δ (= E ′ ′ / E ′), which is the ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the soft polyolefin resin (C). The peak value of is preferably 0.100 or more, more preferably 0.200 or more, and still more preferably 0.300 or more. When the peak value of tan δ of the soft polyolefin resin (C) is 0.100 or more, this is preferable because it contributes to the suppression of unpleasant noise such as rattle and gowagowa.

The thermoplastic resin is a polyolefin resin, and the polyolefin resin is a polyethylene resin (B) having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, and a density of 0.850 g / cm ^{When it has} soft polyolefin resin (C) of ³ or more and less than 0.910 g / cm ³ respectively, mixed composition of the inorganic filler (A), the polyethylene resin (B), and the soft polyolefin resin (C) The ratio is (A) / (B) / (C) = 50% by mass to 75% by mass / 1% by mass to 45% by mass / 1% by mass to 45% by mass (wherein (A) and (B) and (C) and (C)) (A) / (B) / (C) = 50% by mass to 70% by mass / 3% by mass to 43% by mass / 3% by mass). It is more preferable that it is-43 mass% Yes.

In the mixed composition ratio of the inorganic filler (A), the polyethylene resin (B), and the soft polyolefin resin (C), the mixed composition ratio of the inorganic filler (A) is at least the lower limit in the above-mentioned preferable range In some cases, the formation of the pores accompanied by the stretching is sufficient to easily form the communicating holes, and it is easy to develop sufficient air permeability and moisture permeability characteristics.
Moreover, when the mixing composition ratio of the said inorganic filler (A) is below the upper limit in the above-mentioned preferable range, shaping | molding of a resin composition becomes easy and it becomes a thing without a problem in productivity.
When the mixed composition ratio of the polyethylene resin (B) is not less than the lower limit in the above-mentioned preferable range, and the mixed composition ratio of the soft polyolefin resin (C) is not more than the upper limit in the above-mentioned preferable range It becomes a film excellent in heat shrinkage resistance and dimensional stability.
Furthermore, when the mixed composition ratio of the polyethylene resin (B) is not more than the upper limit in the above-mentioned preferable range, and the mixed composition ratio of the soft polyolefin resin (C) is not less than the lower limit in the above-mentioned preferable range And a soft touch such as softness and texture can be obtained, and it is easy to suppress unpleasant noise generated when the film is rubbed.

Meanwhile, as the polyolefin resin, polyethylene resin (B) having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, and a density of 0.850 g / cm ³ or more and 0.910 g / cm ³ You may have the polypropylene resin (D) mentioned later other than the soft polyolefin resin (C) of less than.

<Polypropylene resin (D)>
Polypropylene resin (D) is preferably a density less than 0.890 g / cm ³ or more 0.910 g / cm ^3. The melting point is preferably 140 ° C to 170 ° C. The MFR is preferably 10 to 50 g / 10 min. Here, MFR of a polypropylene resin (D) is a value measured based on the conditions M of JISK7210, and the measurement conditions are 230 degreeC and a 2.16-kg load.

The thermoplastic resin is a polyolefin resin, and the polyolefin resin is a polyethylene resin (B) having a density of 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, a density of 0.850 g / cm ³ or more When the soft polyolefin resin (C) and the polypropylene resin (D) each having less than 0.910 g / cm ^{3 are} contained, the polyethylene resin (B), the soft polyolefin resin (C), and the polypropylene resin (D) (B) / (C) / (D) = 1% by mass to 25% by mass / 50% by mass to 98% by mass / 1% by mass to 25% by mass (wherein (B) and (C) The total mass% of (A) and (D) is 100 mass%.) (B) / (C) / (D) = 5 mass% to 20 mass% / 60 mass% to 90 mass% / 5 mass% to 2 More preferably, it is 0% by mass (however, the total mass% of (B), (C) and (D) is 100% by mass).

In the mixed composition ratio of the polyethylene-based resin (B), the soft polyolefin-based resin (C) and the polypropylene-based resin (D), the mixed composition ratio of the polypropylene-based resin (D) is at least the lower limit in the above-mentioned preferable range When it is, it becomes easy to express sufficient heat resistance to an extending | stretching porous film.
Moreover, when the mixed composition ratio of the said polyethylene-type resin (B) is more than the minimum in the above-mentioned preferable range, shaping | molding of a resin composition becomes easy and it becomes a thing without a problem in productivity.
Furthermore, the mixed composition ratio of the polypropylene resin (D) is not more than the upper limit in the above preferable range, and the mixed composition ratio of the polyethylene resin (B) is not more than the upper limit in the above preferable range, and When the mixed composition ratio of the soft polyolefin resin (C) is equal to or more than the lower limit in the above-mentioned preferable range, a good touch feeling such as softness and texture can be obtained, and unpleasant noise generated when the film rubs can be easily suppressed. .

2-3. Other Components Furthermore, the stretched porous film of the present invention preferably contains the plasticizer (E) in an amount of 0.1% by mass to 8.0% by mass in the resin composition (Z). When the plasticizer (E) is contained at 0.1% by mass or more, the value of tan δ of the resin composition (Z) is increased, and the peak width of tan δ of the resin composition (Z) is further broadened. Can. In addition, the crystal melting enthalpy (ΔHm) of the stretched porous film can be reduced. On the other hand, if the plasticizer (E) is 8.0% by mass or less, bleeding out of the plasticizer can be suppressed, and blocking when the stretched porous film is wound in a roll, and printing failure at the time of printing Can be suppressed.

As a plasticizer (E), the following ester plasticizers are mentioned. Those having a polar structure, for example, monovalent carboxylic acid ester plasticizers (butanoic acid, isobutanoic acid, hexanoic acid, 2-ethylhexanoic acid, hyptanic acid, octylic acid, 2-ethylhexanoic acid, lauric acid etc. And the compounds obtained by the condensation reaction of monohydric carboxylic acids of the formula (I) with polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol and glycerin etc. Specific compounds are exemplified by tri Ethylene glycol di 2-ethylhexanoate, triethylene glycol diisobutanoate, triethylene glycol hexanoate, triethylene glycol di 2-ethyl butanoate, triethylene glycol dilaurate, ethylene glycol di 2-ethyl Xanoate, diethylene glycol di 2-ethylhexanoate, tetraethylene glycol di 2-ethyl hexanoate, tetraethylene glycol diheptanoate, PEG # 400 di 2-ethyl hexanoate, triethylene glycol mono 2-ethyl hexano , Glycerin tri 2-ethylhexanoate, pentaerythritol tetrastearate, dipentaerythritol hexaoctanoate, diglycerin tetrastearate, diglycerin distearate etc., polyvalent carboxylic acid ester plasticizer (adipine) Acid, succinic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid and other polyvalent carboxylic acids, methanol, ethanol, butanol, hexanol, 2-ethyl butanol And compounds obtained by condensation reaction with a monohydric alcohol having 1 to 12 carbon atoms such as heptanol, octanol, 2-ethylhexanol, decanol, dodecanol, butoxyethanol, butoxyethoxyethanol, and benzyl alcohol. For example, dihexyl adipate, di 2-ethylhexyl adipate, diheptyl adipate, dioctyl adipate, di 2-ethylhexyl adipate, di (butoxyethyl) adipate, di (butoxyethoxyethyl) adipate, monoacid adipate (2-ethylhexyl), dibutyl phthalate, dihexyl phthalate, di (2-ethylbutyl) phthalate, dioctyl phthalate, di (2-ethylhexyl) phthalate, benzylbutyl phthalate, didodecyl phthalate, Trioctyl rimetate etc.) Hydroxycarboxylic acid ester plasticizer (monohydric alcohol ester of hydroxycarboxylic acid; methyl ricinoleate, ethyl ricinoleate, butyl ricinoleate, methyl 6-hydroxyhexanoate, ethyl 6-hydroxyhexanoate, 6 Butyl hydroxyhexanoate, polyhydric alcohol ester of hydroxycarboxylic acid; ethylene glycol di (6-hydroxyhexanoate) ester, diethylene glycol di (6-hydroxyhexanoate) ester, triethylene glycol di (6-hydroxyhexanoate) ester , 3-Methyl-1,5-pentanediol di (6-hydroxyhexanoic acid) ester, 3-methyl-1,5-pentanediol di (2-hydroxybutyric acid) ester, 3-methyl-1,5-pen Di- (3-hydroxybutyric acid) ester, 3-methyl-1,5-pentanediol di (4-hydroxybutyric acid) ester, triethylene glycol di (2-hydroxybutyric acid) ester, glycerin tri (ricinoleic acid) ester, L- Any suitable one may be used, such as di (1- (2-ethylhexyl)) tartrate, castor oils, etc., polyester plasticizers, and the like.
Castor oils include conventional castor oil, refined castor oil, hydrogenated castor oil and dehydrated castor oil. The hydrogenated castor oil may, for example, be a hydrogenated castor oil mainly composed of triglyceride composed of 12-hydroxyoctadecanoic acid and glycerin.

In addition to the above-mentioned raw materials, other resin raw materials, recycled resins generated from trimming loss of ears, etc. according to the purpose of use, compatibilizer, processing aid, melt viscosity improver, antioxidant, anti-aging agent , Heat stabilizer, light stabilizer, weather resistant stabilizer, UV absorber, neutralizer, nucleating agent, crosslinking agent, lubricant, anti-blocking agent, slip agent, anti-fogging agent, antibacterial agent, deodorant, hard You may add suitably a flame retardant, an antistatic agent, a coloring agent, a pigment, etc. to the resin composition (Z) which comprises the oriented porous film of this invention.

3. Method for Producing Stretched Porous Film The method for producing a stretched porous film of the present invention is not particularly limited, and it can be produced by a conventionally known method, but it is important to be stretched in at least uniaxial direction.
Here, "film" is meant to encompass from thick sheets to thin films. The film may be planar or tubular, but is preferably planar from the viewpoint of productivity (can be taken as a product in the width direction of the original sheet) and printing on the inner surface. . As a method for producing a flat film, for example, a film obtained by melting the resin composition using an extruder, extruding it from a die into a film, cooling and solidifying it with a cooling roll, air cooling, water cooling (unstretched The film can be exemplified by a method of obtaining a film by stretching the film in at least one uniaxial direction and winding the film with a winder.

Moreover, as a method of obtaining the said unstretched film, after mixing the composition (Z) which comprises the stretched porous film of this invention, it is preferable to carry out melt-kneading. Specifically, after mixing for a suitable time with a mixer such as tumbler mixer, mixing roll, Banbury mixer, ribbon blender, super mixer, etc., an extruder such as a counter-direction twin-screw extruder, co-direction twin-screw extruder, etc. Use to promote uniform distribution of the composition. The obtained resin composition can be molded into a film by connecting a die such as a T-die or a round die to the tip of an extruder. Furthermore, after connecting a strand die to the tip of the kneader and pelletizing it once by a method such as strand cutting or die cutting, introduce the obtained pellet (with a composition to be added if necessary) into a single screw extruder etc. Alternatively, a die such as a T-die or a round die may be connected to the tip of the extruder to form a film. In forming into a film, film forming methods such as inflation molding, tubular molding, T-die molding and the like are preferable. The extrusion temperature is preferably about 180 to 260 ° C., more preferably 190 to 250 ° C. It is also effective to control the dispersion state of the material by optimizing the extrusion temperature and the shear state, to bring various physical properties and mechanical properties of the film described below to desired values.

The stretched porous film of the present invention can be produced by stretching the unstretched film. For example, the resin is melted using an extruder, extruded from a T die or a round die, cooled and solidified by a cooling roll, roll stretching in the longitudinal direction (film flow direction, MD), transverse direction (film flow direction) In at least one direction, such as by tenter stretching in the direction perpendicular to T.D. Moreover, after extending | stretching longitudinally, you may extend | stretch in a horizontal direction, and after extending | stretching transversely, you may extend | stretch in a longitudinal direction. Moreover, you may extend | stretch two or more times in the same direction. Furthermore, after stretching in the longitudinal direction, the film may be stretched in the lateral direction and further stretched in the longitudinal direction. Further, the film may be simultaneously stretched in the longitudinal direction and the lateral direction by the simultaneous biaxial stretching machine. In addition, a tubular non-stretched film may be radially stretched by internal pressure by tubular molding. Furthermore, after stretching the tube-like unstretched film obtained by inflation molding in a folded state, the ear of the folded tube-like stretched porous film is cut, divided into two pieces, and wound respectively. Alternatively, the folded unstretched film may be cut and divided into two unstretched films, which may then be stretched and wound respectively.

In the present invention, it is preferable to perform stretching at least once in the longitudinal direction, and stretching may be performed twice or more in the longitudinal direction in consideration of stretching unevenness and air permeability. The stretching temperature is preferably 0 ° C to 90 ° C, and more preferably 20 ° C to 70 ° C. The total stretching ratio is preferably 1.5 to 6.0 times in total, more preferably 2.0 to 5.0 times. By making the draw ratio 1.5 times or more in total, a stretched porous film can be obtained which is uniformly stretched and has an excellent appearance. On the other hand, by setting the draw ratio to a total of 6.0 times or less, breakage of the film can be suppressed.

If necessary, heat treatment or relaxation treatment can be performed at a temperature of 50 ° C. or more and 120 ° C. or less after stretching for the purpose of reducing the heat shrinkage rate, improving the physical properties, and the like. When stretching is performed by roll stretching, heat treatment can be performed by bringing the stretched film into contact with a heated roll (annealing roll) between the stretching step and the winding step. Moreover, a relaxation process can be performed by making the speed of the roll which contacts next time slower than an annealing roll speed, heating with an annealing roll. Moreover, these heat processing and relaxation processing can also be performed in another process, after extending | stretching an unstretched film and winding up a stretched porous film. If the temperature of the heat treatment or relaxation treatment is too low, the shrinkage of the film is difficult to reduce, and if the temperature is too high, the film may be wound around the roll or the formed micropores may be clogged. Therefore, it is preferable to perform heat treatment or relaxation treatment at a temperature of 50 ° C. or more and 120 ° C. or less. These heat treatments and relaxation treatments may be divided into multiple steps.

In addition, the stretched porous film of the present invention can be subjected to surface treatment such as slit, corona treatment, printing, application of an adhesive, coating, vapor deposition and the like, if necessary.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In addition, the measured value shown to the Example and evaluation were performed as follows. In the examples, the flow direction of the film is described as the "longitudinal" direction (or MD), and the perpendicular direction is referred to as the "lateral" direction (or TD).

(1) Measurement of Dynamic Viscoelasticity of Resin Composition (Z) Constituting Stretched Porous Film In Examples and Comparative Examples shown below, an unstretched film of the resin composition (Z) constituting the stretched porous film is used. , MD: 4 mm, TD: 35 mm using strip-like sample pieces, dynamic viscoelasticity measurement is performed according to the above-mentioned method, storage elastic modulus (E ′), loss elastic modulus (E ′ ′), and , Tan δ (= E ′ ′ / E ′), which is the ratio of storage elastic modulus (E ′) to loss elastic modulus (E ′ ′). Thereafter, when tan δ was 0.100 or more at −20 ° C., it was determined as “A”, and when tan δ was less than 0.100 at −20 ° C., it was determined as “B”.
Furthermore, E ′ (unit: × 10 ⁸ Pa) at 20 ° C., and tan δ values at −30 ° C., −20 ° C., −10 ° C., 0 ° C., 10 ° C., 20 ° C., and 30 ° C. are shown in Table 1 I gave up to ~ 3.

(2) Basis Weight of Stretched Porous Film The basis weight of the stretched porous film was calculated according to the method described above.

(3) Porosity of Stretched Porous Film The porosity of the stretched porous film was calculated according to the method described above.

(4) Air Permeability of Stretched Porous Film The air permeability of the stretched porous film was calculated according to the method described above. As the air permeability measuring device, an Oken type air permeability measuring machine EGO1-55 manufactured by Asahi Seiko Co., Ltd. was used.

(5) Moisture Permeability of Stretched Porous Film The moisture permeability of the stretched porous film was calculated according to the method described above.

(6) Tensile Breaking Strength in Stretching Direction of Stretched Porous Film According to the method described above, the tensile breaking strength in the stretching direction of the stretched porous film (this example, MD in the comparative example) was calculated.

(7) Tensile Breaking Elongation of Stretched Porous Film in Stretching Direction According to the method described above, tensile breaking elongation of the stretched porous film in the stretching direction (this example, MD in the comparative example) was calculated.

(8) Thermal Shrinkage of Stretched Porous Film In Examples 101 to 104 and Comparative Examples 101 to 102, the stretching direction of the stretched porous film when heated at 60 ° C. for 1 hour according to the method described above (this example, comparative example Then, the thermal contraction rate in MD) was calculated.

(9) Total Light Transmittance of Stretched Porous Film The total light transmittance of the stretched porous film was calculated according to the method described above.

(10) Crystal melting peak (Pm), crystal melting enthalpy (ΔHm) of stretched porous film
The stretched porous film obtained in the following examples and comparative examples is heated from -40 ° C to 200 ° C at a heating rate of 10 ° C / minute using a differential scanning calorimeter (DSC), and held for 1 minute The temperature is then lowered from 200 ° C. to −40 ° C. at a cooling rate of 10 ° C./min, held for 1 minute, and further raised again from −40 ° C. to 200 ° C. at a heating rate of 10 ° C./min. The crystal melting enthalpy (ΔHm) of the stretched porous film was calculated from the crystal melting peak (Pm) in the temperature rising process and the peak area of the crystal melting peak (Pm) in the reheating process.
In Examples 201 to 205 and Comparative Examples 201 to 204, the presence or absence of a crystal melting peak (Pm1) was confirmed at 140 ° C. to 200 ° C. at this time. Further, peak temperature (Tm1) and crystal melting enthalpy (ΔHm1) were calculated from the above (Pm1). Similarly, the presence or absence of a crystal melting peak (Pm2) was confirmed at 30 ° C. to 130 ° C. Further, the peak temperature (Tm2) and the crystal melting enthalpy (ΔHm2) were calculated from the above (Pm2).

(11) Flexibility of Stretched Porous Film The stretched porous film obtained in the following Examples and Comparative Examples is cut out in the longitudinal direction (MD) 1000 mm and the transverse direction (TD) 200 mm, and it is touched by hand according to the following judgment criteria ,evaluated.
A: I feel a soft texture on the film.
B: I feel the hardness of the film.

(12) Uncomfortable sound of the stretched porous film The unpleasant sound of the stretched porous film was evaluated by the following test or the measurement of unpleasant noise.

(12-1) Discomfort Sound Due to Friction of Stretched Porous Film The stretched porous film obtained in the following examples and comparative examples is cut out in the longitudinal direction (MD) 1000 mm and the transverse direction (TD) 200 mm, and the films are rubbed together Were evaluated according to the following judgment criteria.
A: There is no unpleasant sound when rubbing.
B: When I rub it on, I feel an unpleasant sound.

(12-2) Measurement of discomfort noise of stretched porous film Measurement of discomfort noise of stretched porous film measures individual locations with a width of about 3 m, a length of about 4 m, and a height of about 3 m (under an environment where the influence of external noise is small The frequency weighting characteristic is an A characteristic, and the time weighting characteristic is an F characteristic, using a sound level meter NL-42 manufactured by Lion Corporation.
First, the stretched porous films obtained in the examples and comparative examples shown below were cut out in the longitudinal direction (MD) 400 mm and the transverse direction (TD) 200 mm, folded once at the center in the longitudinal direction, and folded in two. Thereafter, the TD end portions of the laminated stretched porous film were sandwiched, and the distance between the held TD end portions was adjusted to 100 mm.
Furthermore, after adjusting the distance between the stretched porous film held thereby and the microphone (sound collecting portion) of the ordinary sound level meter to be 100 mm, the MD and TD in the direction perpendicular to the held stretched porous film (thickness direction The film was rubbed by vibrating the clamped end three times back and forth in 1 second, and the time average sound level (LAeq) in 10 seconds of measurement time was measured and evaluated according to the following judgment criteria.
In addition, the time average sound level (LAeq) in 10 seconds of measurement time in the state which does not vibrate a film (non-operating state) was 26 dB.
A: Time average sound level (LAeq) is 26 dB or more and less than 35 dB B: Time average sound level (LAeq) is 35 dB or more and less than 45 dB C: Time average sound level (LAeq) is 45 dB or more

(13) Breaking Heat Resistance Temperature of Stretched Porous Film In each of Examples 201 to 205 and Comparative Examples 201 to 204, the breaking heat resistance temperature was evaluated according to the above-mentioned method. The evaluation was made by setting the temperature in the bath of the convection oven at 120 ° C., 140 ° C., and 160 ° C., leaving the bath in the bath for 2 minutes and heating, according to the following judgment criteria by visual evaluation.
A: There are no tears or holes in the sample of the circular punching point of the stainless steel plate.
B: The sample at the circular punching point of the stainless steel plate is melted and the hole is open.

(14) Overall Evaluation (14-1) Examples 101 to 104 and Comparative Examples 101 to 102
In view of the evaluations shown in the above (1) to (12), comprehensive evaluations were made according to the following criteria.
A: A film suitable for applications requiring breathability and moisture permeability, having excellent feel such as flexibility and texture, and suppressing the generation of unpleasant sound generated when the film is rubbed.
B: A film that has excellent feel such as flexibility and texture and is excellent in air permeability and moisture permeability, but is a film that feels the generation of unpleasant noise.
C: A film excellent in air permeability and moisture permeability, but it is a film which does not feel a sense of flexibility or texture and feels the generation of an unpleasant sound.
D: A film having insufficient physical properties required for a stretched porous film such as air permeability and moisture permeability.
(14-2) Examples 105 to 108 and Comparative Examples 103 to 104
In view of the evaluations described in (1) to (7) and (9) to (12) above, comprehensive evaluation was performed on the basis of the following criteria.
A: A film suitable for applications requiring breathability and moisture permeability, having excellent feel such as flexibility and texture, and suppressing the generation of unpleasant sound generated when the film is rubbed.
B: A film that has excellent feel such as flexibility and texture and is excellent in air permeability and moisture permeability, but is a film that feels the generation of unpleasant noise.
C: A film excellent in air permeability and moisture permeability, but it is a film which does not feel a sense of flexibility or texture and feels the generation of an unpleasant sound.
D: A film having insufficient physical properties required for a stretched porous film such as air permeability and moisture permeability.
(14-3) Examples 201 to 205 and Comparative Examples 201 to 204
In view of the evaluations shown in the above (1) to (7) and (9) to (13), comprehensive evaluations were performed on the basis of the following criteria.
A: A film suitable for applications requiring breathability and moisture permeability, with excellent feel such as flexibility and texture, and suppressing the generation of unpleasant noise generated when rubbing the film, and sufficient heat resistance Film that combines
B: A film suitable for applications requiring breathability and moisture permeability, which has excellent tactile sensation such as flexibility and texture and suppresses the generation of unpleasant noise generated when rubbing the film, but heat resistance is insufficient It is.
C: A film excellent in air permeability and moisture permeability, but it is a film which does not feel a sense of flexibility or texture and feels the generation of an unpleasant sound.
D: A film having insufficient physical properties required for a stretched porous film such as air permeability and moisture permeability.

Raw materials used in each example and comparative example are as follows.
<Inorganic filler (A)>
Heavy calcium carbonate “Lighton BS-0” (average particle diameter 1.1 μm, stearic acid surface-treated product) manufactured by Bihoku Powder Chemical Industry Co., Ltd. Hereinafter, it is abbreviated as "A-1".
<Polyethylene resin (B)>
-Japanese polyethylene Co., Ltd. linear low density polyethylene "Novatec LL UF230" (density 0.921 g / cm ³ , MFR 1.0 g / 10 min, melting point 121 ° C.). Hereinafter, it is abbreviated as "B-1".
-Branched low-density polyethylene "Novatec LD LF441" manufactured by Japan Polyethylene Corporation (density 0.918 g / cm ³ , MFR 2.3 g / 10 min, melting point 113 ° C.). Hereinafter, it is abbreviated as "B-2."
<Soft polyolefin resin (C)>
· A metallocene ethylene / α-olefin copolymer "Keel KF 360 T" (density 0.898 g / cm ³ , MFR 3.5 g / 10 min, melting point 90 ° C.), manufactured by Japan Polyethylene Corporation. Hereinafter, it is abbreviated as "C-1".
-Dow Chemical Co., ethylene / octene block copolymer "Infuse D 910 0.05" (density 0.877 g / cm ³ , MFR 1.0 g / 10 min, melting point 120 ° C.). Hereinafter, it is abbreviated as "C-2."
Mitsui Chemicals Co., Ltd., ethylene / 1-butene copolymer "TAFMER A1050S" (density 0.862g ^/ cm 3, MFR1.2g ^/ 10 min, melting point 45 ° C.). Hereinafter, it is abbreviated as "C-3".
-Dow Chemical Co., ethylene / octene block copolymer “Infuse D9107” (density 0.866 g / cm ³ , MFR 1 g / 10 min, melting point 119 ° C.). Hereinafter, it is abbreviated as "C-4".
<Polypropylene resin (D)>
Polypropylene “Novatec PP SA03” (density 0.900 g / cm ³ , MFR ³⁰ g / 10 min, melting point 165 ° C.) manufactured by Japan Polypropylene Corporation. Hereinafter, it is abbreviated as "D-1".
<Plasticizer (E)>
-Kaif Trading Co., Ltd., hardened castor oil "HCO-P3". Hereinafter, it is abbreviated as "E-1".
-A liquid polyester plasticizer "Diacsizer D600" manufactured by J-plus Co., Ltd. Hereinafter, it is abbreviated as "E-2."
<Antioxidant>
-BASF Japan Ltd. make, antioxidant "Irganox B225." Hereinafter, it is abbreviated as "F-1".
<Other resin>
Mitsui Chemicals Co., Ltd., alpha-olefin copolymer "Abusotoma EP-1001" (density 0.84g ^/ cm 3, MFR10g ^/ 10 min (230 ° C. 2.16 kg load)). Hereinafter, it is abbreviated as "G-1".

Example 101
Each raw material is weighed according to the composition ratio shown in Table 1, then charged in a Henschel mixer, mixed and dispersed for 5 minutes, and melt-kneaded at a set temperature of 200 ° C. using a co-directional twin-screw extruder The resin composition was extruded with a T-die connected to the tip of a co-directional twin-screw extruder, pulled out with a casting roll set at 50 ° C., and cooled and solidified to obtain an unstretched film. Dynamic viscoelasticity measurement was performed on the obtained unstretched film.
Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 130% (draw ratio: 2.3 times), (T)-(U) draw ratio 130% (draw ratio: 2.3 times) was multiplied to give a total draw of 5.3 times in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

Example 102
In the same manner as in Example 101, an unstretched film was collected. Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 100% (stretching ratio: 2.0 times) and (T)-(U) draw ratio 100% (stretching ratio: 2.0 times) were applied to make a total of 4.0 times stretching in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

<Example 103>
In the same manner as in Example 101, an unstretched film was collected. Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) ) Draw ratio 70% (stretching ratio 1.7 times), (T)-(U) draw ratio 70% (stretching ratio 1.7 times), and the film was stretched in total by 2.9 times in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

Comparative Example 101
In the same manner as in Example 101, an unstretched film was collected. Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 40% (stretching ratio: 1.4 times) and (T)-(U) draw ratio 40% (stretching ratio: 1.4 times) were applied to perform a total stretching of 2.0 times in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

<Example 104>
Each raw material is weighed according to the composition ratio shown in Table 1, then charged in a Henschel mixer, mixed and dispersed for 5 minutes, and melt-kneaded at a set temperature of 200 ° C. using a co-directional twin-screw extruder The resin composition was extruded with a T-die connected to the tip of a co-directional twin-screw extruder, pulled out with a casting roll set at 50 ° C., and cooled and solidified to obtain an unstretched film. Dynamic viscoelasticity measurement was performed on the obtained unstretched film.
Thereafter, between the roll (S) set to 20 ° C., the roll (T) set to 20 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 100% (stretching ratio: 2.0 times) and (T)-(U) draw ratio 100% (stretching ratio: 2.0 times) were applied to make a total of 4.0 times stretching in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

Comparative Example 102
Each raw material is weighed according to the composition ratio shown in Table 1, then charged in a Henschel mixer, mixed and dispersed for 5 minutes, and melt-kneaded at a set temperature of 200 ° C. using a co-directional twin-screw extruder The resin composition was extruded with a T-die connected to the tip of a co-directional twin-screw extruder, pulled out with a casting roll set at 50 ° C., and cooled and solidified to obtain an unstretched film. Dynamic viscoelasticity measurement was performed on the obtained unstretched film.
Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 130% (draw ratio: 2.3 times), (T)-(U) draw ratio 130% (draw ratio: 2.3 times) was multiplied to give a total draw of 5.3 times in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 1.

The stretched porous films obtained in Examples 101 to 104 were films having excellent air permeability and moisture permeability, and also having suitable tensile strength at break, tensile elongation at break, heat shrinkage, and total light transmittance. . In addition, even when the stretched porous films obtained in Examples 101 to 104 were rubbed together, no unpleasant sound was felt.
The results show that the tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the present invention and the porosity of the stretched porous film satisfy the range specified in the present invention. Is considered to be Specifically, tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of Examples 101 to 104 is 0.100 or more at −20 ° C., It is considered that the sound propagating by vibrating the resin composition (Z) is attenuated and contributes to the suppression of the unpleasant sound. In addition, since the porosity of the stretched porous films of Examples 101 to 104 is in the range of 25% to 80%, the sound propagating through the communicated voids is the sound of the voids and the wall surface of the resin composition (Z). It is thought that the number of energy losses that occur during a collision increases and contributes to the suppression of unpleasant noise.
On the other hand, the film obtained in Comparative Example 101 is a film using the resin composition (Z) satisfying the above-mentioned definition of tan δ defined in the present invention as in Examples 101 to 103, but Comparative Example The stretched porous film obtained in 101 deviates from the porosity defined in the present invention. Therefore, although the film obtained in Comparative Example 101 is excellent in touch such as flexibility and texture, it was insufficient for suppression of unpleasant noise.
Moreover, although the film obtained in Comparative Example 102 satisfies the porosity defined by the present invention, tan δ at −20 ° C. is less than 0.100, which is insufficient for suppression of unpleasant noise. The
That is, it is important that both the above-mentioned tan δ and the porosity satisfy the range defined by the present invention in order to achieve both the excellent feel and the suppression of the unpleasant noise generated when the film is rubbed. I understand.

Example 105
Each raw material is weighed according to the composition ratio shown in Table 2, then charged in a Henschel mixer, mixed and dispersed for 5 minutes, and melt-kneaded at a set temperature of 200 ° C. using a co-directional twin-screw extruder The resin composition was extruded with a T-die connected to the tip of a co-directional twin-screw extruder, pulled out with a casting roll set at 50 ° C., and cooled to solidify to obtain an unstretched film with a thickness of 30 μm. Dynamic viscoelasticity measurement was performed on the obtained unstretched film.
Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 100% (stretching ratio: 2.0 times) and (T)-(U) draw ratio 100% (stretching ratio: 2.0 times) were applied to make a total of 4.0 times stretching in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

<Example 106>
An unstretched film with a thickness of 30 μm was collected by the same method as in Example 105 except that the raw materials were changed to the composition ratios shown in Table 2. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 105 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

Example 107
An unstretched film with a thickness of 30 μm was collected by the same method as in Example 105 except that the raw materials were changed to the composition ratios shown in Table 2. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 105 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

<Example 108>
An unstretched film with a thickness of 50 μm was collected by the same method as in Example 105 except that the raw materials were changed to the composition ratios shown in Table 2. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 105 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

Comparative Example 103
An unstretched film with a thickness of 50 μm was collected by the same method as in Example 105 except that the raw materials were changed to the composition ratios shown in Table 2. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 105 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

Comparative Example 104
An unstretched film with a thickness of 50 μm was collected by the same method as in Example 105 except that the raw materials were changed to the composition ratios shown in Table 2. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 105 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 2.

The stretched porous films obtained in Examples 105 to 108 were films excellent in air permeability and moisture permeability as well as having suitable tensile strength at break, tensile elongation at break and total light transmittance. In addition, the time average sound level (LAeq) when the stretched porous films obtained in Examples 105 to 108 were rubbed together showed a low value, and no unpleasant sound was felt.
The results satisfy tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the present invention, and the range in which the porosity of the stretched porous film is defined in the present invention, And, it is considered that the crystal melting enthalpy (ΔHm) of the stretched porous film is 10 g / J to 45 g / J. Specifically, tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of Examples 105 to 108 is 0.100 or more at −20 ° C., It is considered that the sound propagating by vibrating the resin composition (Z) is attenuated and contributes to the suppression of the unpleasant sound. In addition, since the crystal melting enthalpy (ΔHm) of the stretched porous films of Examples 1 to 4 is in the range of 10 J / g to 45 J / g, there are few crystal components that repel and vibrate when an external force is applied. It is thought that the sound to be
On the other hand, the films obtained in Comparative Examples 103 and 104 do not satisfy the preferable range of tan δ specified in the present invention or the crystal melting enthalpy (ΔHm), so they are insufficient for suppressing unpleasant noise, and the time average Sound level (LAeq) showed a high value.
That is, it is important that the above-mentioned tan δ and the porosity of the stretched porous film satisfy the range defined by the present invention in order to achieve both the excellent feel and the suppression of the unpleasant noise generated when the film is rubbed. It is understood that the crystal melting enthalpy (ΔHm) of the stretched porous film is preferably in the range of 10 g / J to 45 g / J.

Example 201
Each raw material is weighed according to the composition ratio shown in Table 3, then charged in a Henschel mixer, mixed and dispersed for 5 minutes, and melt-kneaded at a set temperature of 200 ° C. using a co-directional twin-screw extruder The resin composition was extruded with a T-die connected to the tip of a co-directional twin-screw extruder, pulled out with a casting roll set at 50 ° C., and cooled to solidify to obtain an unstretched film with a thickness of 35 μm. Dynamic viscoelasticity measurement was performed on the obtained unstretched film.
Thereafter, between the roll (S) set to 60 ° C., the roll (T) set to 60 ° C., and the roll (U) set to 60 ° C., the obtained unstretched film is (S)-(T) A draw ratio of 100% (stretching ratio: 2.0 times) and (T)-(U) draw ratio 100% (stretching ratio: 2.0 times) were applied to make a total of 4.0 times stretching in MD. Subsequently, the stretched porous film was obtained by performing heat treatment and relaxation treatment with a roll (V) set to 90 ° C. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Embodiment 202
An unstretched film with a thickness of 35 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Embodiment 203
An unstretched film with a thickness of 35 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Embodiment 204
An unstretched film with a thickness of 35 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Embodiment 205
An unstretched film with a thickness of 35 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Comparative Example 201
An unstretched film with a thickness of 50 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Comparative Example 202
An unstretched film with a thickness of 50 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Comparative Example 203
An unstretched film with a thickness of 30 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

Comparative Example 204
An unstretched film with a thickness of 35 μm was collected by the same method as in Example 201 except that the raw materials were changed to the composition ratios shown in Table 3. Dynamic viscoelasticity measurement was performed on the obtained unstretched film. Thereafter, the obtained unstretched film is stretched, heat-treated and relaxed in the same manner as in Example 201 to obtain a stretched porous film. Various evaluations were performed on the obtained stretched porous film. The results are summarized in Table 3.

The stretched porous films obtained in Examples 201 to 205 were films excellent in air permeability and moisture permeability as well as having suitable tensile strength at break, tensile elongation at break, and total light transmittance. In addition, the time average sound level (LAeq) when the stretched porous films obtained in Examples 201 to 205 were rubbed together showed a low value, and no unpleasant sound was felt. Furthermore, in the film rupture heat resistance test, the film did not rupture at 120 ° C., 140 ° C., and even at 160 ° C.
The results show that the tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of the present invention and the appearance temperature of the crystal melting peak satisfy the range specified by the present invention It is thought that it is for. Specifically, tan δ calculated from the dynamic viscoelasticity measurement of the resin composition (Z) constituting the stretched porous film of Examples 201 to 205 is 0.100 or more at −20 ° C., It is considered that the sound propagating by vibrating the resin composition (Z) is attenuated and contributes to the suppression of the unpleasant sound. Further, since the stretched porous films obtained in Examples 201 to 205 have crystal melting peaks at 140 ° C. to 200 ° C., they were shown to have high heat resistance.
On the other hand, since the films obtained in Comparative Examples 201 and 202 do not satisfy tan δ prescribed by the present invention, they are insufficient for suppressing unpleasant noise, and the time average sound level (LAeq) shows a high value. . Also, the film obtained in Comparative Example 203 is a film that is soft and suppresses unpleasant noise because it does not have a crystal melting peak in the range of 140 ° C. to 200 ° C., but the heat resistance required for the stretched porous film is It turns out that it is somewhat inadequate.
Furthermore, Comparative Example 204 is a film containing an α-olefin copolymer having a density of less than 0.850 g / cm ³ , but because the film does not satisfy tan δ specified by the present invention, it is insufficient for suppressing unpleasant noise. Met. That is, in order to achieve both the heat resistance required for the stretched porous film and the suppression of the unpleasant noise generated when the film rubs, both the above-mentioned tan δ and the temperature at which the crystal melting peak appears are the present invention. It is understood that it is important to satisfy the specified range.

While the present invention has been described above in connection with the embodiments that are presently most practical and preferred, the present invention is not limited to the embodiments disclosed herein. Rather, it can be suitably modified without departing from the scope of the invention or the spirit of the invention which can be read from the claims and the specification as a whole, and a stretched porous film with such a modification is also included in the technical scope of the present invention It must be understood as.

The stretched porous film of the present invention has an excellent tactile sensation such as flexibility and texture, and also suppresses the generation of unpleasant sound generated when the film is rubbed, and is also excellent in air permeability, moisture permeability and strength. Therefore, sanitary products such as disposable diapers and feminine hygiene products using stretched porous film; clothing such as work clothes, jumpers, jackets, medical clothes, chemical protective clothes, etc. Furthermore, masks, covers, drapes, sheets, wraps Etc. It can utilize suitably for the use by which air permeability, moisture permeability, etc. are calculated | required.

Claims

A stretched porous film comprising a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A),
The ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z), tan δ (= E ′ ′ / E ′), is −20. A stretched porous film having a porosity of 25% to 80% at 0.10 ° C or more.
The stretched porous film according to claim 1, which has a crystal melting enthalpy (ΔHm) of 10 J / g to 45 J / g.
A stretched porous film comprising a thermoplastic resin and a resin composition (Z) containing an inorganic filler (A),
The ratio of the storage elastic modulus (E ′) to the loss elastic modulus (E ′ ′) calculated from the dynamic viscoelasticity measurement of the resin composition (Z), tan δ (= E ′ ′ / E ′), is −20. A stretched porous film having a crystal melting peak (Pm1) at 140 ° C. to 200 ° C., which is 0.100 or more in ° C.
The stretched porous film according to claim 3, wherein a crystal melting enthalpy (ΔHm1) calculated from the crystal melting peak (Pm1) is 1 J / g to 10 J / g.
The crystal melting peak (Pm2) is further provided at 30 ° C. to 130 ° C., and the crystal melting enthalpy (ΔHm2) calculated from the crystal melting peak (Pm2) is 10 J / g to 45 J / g. The oriented porous film of description.
The stretching according to any one of claims 1 to 5, comprising the resin composition (Z) containing 25% by mass to 54% by mass of the thermoplastic resin and 46% by mass to 75% by mass of the inorganic filler (A). Porous film.
The stretched porous film according to any one of claims 1 to 6, wherein the thermoplastic resin is a polyolefin resin.
The stretched porous film according to claim 7, wherein the density of the polyolefin resin is 0.850 g / cm 3 or more and 0.940 g / cm 3 or less.
As said polyolefin resin, polyethylene resin (B) whose density is 0.910 g / cm 3 or more and 0.940 g / cm 3 or less, and soft whose density is 0.850 g / cm 3 or more and less than 0.910 g / cm 3 The stretched porous film according to claim 7 or 8, each having a polyolefin resin (C).
The storage elastic modulus (E ') calculated from the dynamic viscoelasticity measurement of the said resin composition (Z) is 8.0 * 10 < 8 > Pa or less in 20 degreeC, The said any one of Claims 1-9 Stretched porous film.
The stretched porous film according to any one of claims 1 to 10, which has a moisture permeability of 1000 g / (m 2 · 24 h) to 15000 g / (m 2 · 24 h).
The stretched porous film according to any one of claims 1 to 11, which has a tensile breaking strength in the stretching direction of 7 N / 25 mm or more.
The stretched porous film according to any one of claims 1 to 12, which has a tensile elongation at break in the stretching direction of 40% to 400%.
The stretched porous film according to any one of claims 1 to 13, wherein the resin composition (Z) contains 0.1% by mass to 8.0% by mass of a plasticizer (E).
A sanitary product using the stretched porous film according to any one of claims 1 to 14.
A garment using the stretched porous film according to any one of claims 1 to 14.